Method for providing alignment of a probe

ABSTRACT

A method for aligning a probe relative to a supporting substrate defining a first planar surface, an edge, and a first crystal plane includes the steps of masking the surface of the substrate to define an exposed area on the first surface at the edge; and etching, using an etch reagent, a recess in the exposed area, the recess defining first and second opposed sidewalls, an end wall remote from the edge, and a bottom wall. The method further includes the step of providing a probe substrate defining a second planar surface and a second crystal plane identical to the first crystal plane, and positioning the probe substrate so that the first and the second crystal planes are positioned identically when forming a probe from the probe substrate using the etch reagent, wherein the probe defines congruent surfaces to the first and second sidewalls.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a national phase filing, under 35 U.S.C. §371(c), ofInternational Application No. PCT/DK2005/000417, the disclosure of whichis incorporated herein by reference in its entirety.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

The present invention relates to a method for providing alignment of aprobe relative to a supporting substrate.

The present invention further relates to a method for testing electricalproperties of test samples. Still further, the present invention relatesto probes for testing electrical properties on a specific location of atest sample. Specifically the present invention further relates to testprobes including a cantilever part. Even further, the present inventionrelates to testing apparatuses for testing electrical properties of testsamples.

Reference is made to the patent publications U.S. Pat. Nos. 6,358,762,5,811,017, WO 03/096429, U.S. Pat. Nos. 6,232,143 , 5,475,318, WO03/046473, EP 0 886 758, EP 0 974 845, EP 1 095 282, U.S. Pat. Nos.6,479,395, 5,545,291, 5,347,226, 6,507,204, 6,343,369, 5,929,438 and US2002/174715, all of which are hereby incorporated in the presentspecification by reference in their entirety for all purposes.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention a probe for testingelectric properties on a specific location of a test sample is provided.The probe may comprise:

a supporting body defining opposite first and second parts constitutinga flexible cantilever part being predominantly flexible in one directionand a base part respectively, the cantilever part defining an outerplanar surface substantially perpendicular to the one direction, thebase part being adapted for being fixated in a co-operating testingmachine,

at least one conductive probe arm in the cantilever part, each of the atleast one conductive probe arm being positioned opposite the base part,

-   -   the cantilever part defining opposite first and second regions,        the second region being in contact with the base part, the first        region defining first and second side surfaces, each of the        first and second side surfaces defining a first angle with the        outer planar surface, a first width defined between the first        and the second side surfaces, the second region defining third        and fourth side surfaces, each of the third and fourth side        surfaces defining a second angle with the outer planar surface,        a second width defined between the third and the fourth side        surfaces, and    -   the second width being equal to or smaller than the first width.

The supporting body constitutes the entire probe, and may be formed as asingle unitary piece or by assembling two or more pieces. The probe mayfurther comprise a first transitional area between the areas definingthe first and second widths.

The conductive probe arms may be freely extending from the cantileverpart opposite the base part thereby giving each of the conductive probearms flexible motion. However, the conductive probe arms mayalternatively be formed not extending from the cantilever part, butpossibly near or at an edge of the cantilever part. The conductive probearms may be positioned at any of the surfaces of the cantilever part.

The term “predominantly flexible in one direction” is to be understoodas the distal part of the probe flexible in one direction, but alsoflexible in other directions, so that if the probe is brought in contactwith a test sample, whilst being tilted, the flexibility in multipledirections enables a perfect or near perfect alignment of the probe withthe test sample.

The probe may include a third area defining a third width on or in thesupporting body. The third width may be equal to the first or secondwidth. Alternatively, the third width may be different from both thefirst and second widths.

The cantilever part may include a part where the thickness of the distalend is thicker than other parts of the cantilever part. The probe headmay include a protruding or ridge part.

According to the teachings of the present invention the first and secondside surfaces may be substantially parallel the third and fourth sidesurfaces may be substantially parallel. The first and second sides, andcorrespondingly third and fourth sides, may also define an angle betweenthem, thereby possibly giving the cantilever part a wedge form or aV-form. The first, second, third and fourth sides need not be defined inthe entire area constituting the sides of the cantilever part. Whenproducing probes of this sort, the production method includes etchingwhich in real world applications does not product perfect planarsurfaces.

According to the teachings of the present invention the first angle maybe 60 to 90 degrees the second angle may be approximately 60 to 90degrees, preferably below 90 degrees. The first angle may be 0 to 90degrees, such as 5 to 89 degrees, such as 10 to 80 degrees, such as 15to 75 degrees, such as 20 to 70 degrees, such as 25 to 60 degrees, suchas 30 to 56 degrees, such as 44 to 55 degrees, such as 0 to 5 degrees,such as 5 to 15 degrees, such as 15 to 25 degrees, such as 25 to 35degrees, such as 35 to 45 degrees, such as 45 to 50 degrees, such as 50to 55 degrees, such as 55 to 65 degrees, such as 65 to 75 degrees, suchas 75 to 85 degrees, such as 85 to 90 degrees, preferably 54.7 degreesor 45 degrees or 46.5 degrees, or 35.3 degrees or 33.5 degrees.

The first angle may be identical to or different from the second angle.The angle or angles may be defined between any of the surfaces in anydirection possible. The angled sides is contemplated to decrease theoverall weight of the probe head and also to give the probe anadvantageous shape for easing or improving the way the probe head isbrought into contact with the test sample.

An object of the present invention is to provide a probe where the firstregion further defines a first top surface and an opposite, parallelfirst bottom surface, and the second region further defines a second topsurface and an opposite, parallel second bottom surface, the base partdefining a third top surface, the first, the second and the third topsurface being substantially parallel,

-   -   the outer planar surface being constituted by the first top        surface and/or the second top surface,    -   a first thickness defined between the first top surface and the        first bottom surface,    -   a second thickness defined between the second top surface and        the second bottom surface,    -   the second thickness being smaller than or equal to the first        thickness.

The first and the second thickness are preferably not equal, therebydefining a probe having a part where the probe is attenuated, possiblybeing an area between a base part and the distal end of the cantileverpart. Surprisingly, the thinned or attenuated area gives the probe anadvantageous flexibility compared to probes known in the art.

The probe according to the teachings of the present invention mayinclude an attenuated or thinned area in the cantilever arm. Thecantilever arm may be attenuated in one, two or three dimensions,alternatively in any combinations thereof.

The ratio between the first and the second thickness may be 1:1,05 to1:50, such as 1:1,5 to 1:40, such as 1:2 to 1:30, such as 1:2,5 to 1:20,such as 1:3 to 1:10, such as 1:4 to 1:5, such as 1:1,05 to 1:2, such as1:2 to 1:3, such as 1:3 to 1:5, such as 1:5 to 1:10, such as 1:10 to1:20, such as 1:20 to 1:50. The smaller or thinner area is contemplatedto increase or give an advantageous flexibility to the probe.

As previously mentioned, the physical embodiment of the presentinvention will not, in the mathematical sense, be precisely or perfectlyplanar; however in the present context the substantially planar surfacesare to be construed as perfectly planar.

According to a specific feature of the present invention the secondthickness may be defined across the entire second region a specific partof the second region. Meaning that the area where the second region hasa different thickness that the first region may be restricted to aspecific area rather than the entire area. Thereby an embodiment havinga specific area in the second region with either a smaller or largerthickness than the first region may be produced. The area having adifferent thickness is contemplated to provide flexibility to the probe.

According to a first feature of the present invention the first topsurface and the second top surface may be substantially coplanar.

According to a second feature of the present invention the first topsurface and the third top surface may be substantially coplanar.

According to a third feature of the present invention the second topsurface and the third top surface being substantially coplanar.

According to a fourth feature of the present invention none of thefirst, second or third top surfaces may be substantially coplanar.

According to a fifth feature of the present invention the first and thesecond bottom surfaces may be substantially coplanar.

The above-mentioned first, second, third, fourth and fifth features maybe utilized individually or in any combinations.

It is an advantage of the present invention that the second region mayinclude at least one aperture extending from the second top surface tothe second bottom surface. Probes having one aperture may be desirablewhen placing conductive probe arms in the cantilever part, since thereis a need for placing electrical conductive paths from each of theconductive probe arms to a co-operating testing machine. Also a probehaving one large aperture or opening may enable the sides of theconnecting area to function as a hinge or the like, providing a highdegree of flexibility. The use of an aperture or apertures iscontemplated to provide more flexibility to the cantilever probe. Thehinge mechanism described above is also contemplated to be present inembodiments including more than one aperture and/or thinned area orareas.

The probe may include a transitional area between the parts havingdifferent thicknesses. The transitional area may define angled surfaces.

Surprisingly, forming an L-shaped structure in one or more sides of anaperture in the second region moves or changes the point where the probewill flex when brought into contact with the test area of the testsample. The L-shaped structure may be formed in two sides with one ormore apertures defined in between them.

In alternative embodiments, the second region may include recessesinstead of apertures whereby one or more basins or recesses are formedin the second region. The basins are contemplated to improve theflexibility of the cantilever part of the test probes compared to thetest probes known in the art.

It is a further advantage of the present invention that the secondregion may include at least one indentation, notch, depression, dent,recess, dimple or any combinations thereof, extending less than thesecond thickness. The indentation, cut, incision, notch, nick, dimple orserration constitutes an area or volume of the probe where material hasbeen removed, has never been present. The reduced amount of material iscontemplated to provide more flexibility to the cantilever probe.

It is a particular advantage of the present invention that at least oneof the apertures or the indentations may define an opening having asubstantially circular geometry, a substantially oval geometry, asubstantially square geometry, a substantially oblong geometry, asubstantially triangular geometry, a truncated triangular geometry, anypolygonal geometry or any combinations thereof.

According to a first object of the present invention the second regionmay include at least one groove in the second top surface in the secondbottom surface.

According to a second object of the present invention at least onegroove may extend from the third side to the fourth side. Also the atleast one groove may extend less that the second width, either from thethird or fourth sides. Further alternatively the groove may extend fromeither the third or fourth sides in an angle in relation with the sidefrom which the groove extends.

The groove or grooves are contemplated to provide more flexibility tothe cantilever probe.

Furthermore at least one of the grooves may define a roundedcross-section, a square cross-section, a rectangular cross-section, atriangular cross-section, a truncated triangular cross-section, anypolygonal cross-section or any combination thereof.

It is a specific advantage of the present invention that the third thefourth side may include a trench extending at least partly from thesecond top surface to the second bottom surface or from the secondbottom surface to the second top surface. Also the trench may define arounded cross-section, a square cross-section, a rectangularcross-section, a triangular cross-section, a truncated triangularcross-section or any combination thereof. The trench or trenches arecontemplated to provide more flexibility to the cantilever probe.

The trench or the groove, alternatively both the trench and the groove,may have varying depths along the path of which the groove extends.Preferably the groove or trench has substantially the same depth alongthe path of which it extends.

According to a specific feature of the present invention the cantilevermay made from a metallic material, an alloying, a semiconductormaterial, a crystalline or amorphous material, or any combinationthereof. Preferably, the device may be made from SiO₂, Si₃N₄, or Si, andmay be a SOI device or alternatively a layered structure comprising anyof the mentioned materials.

It is an object of the present invention to include conductive paths forestablishing electrical connections to each of the plurality ofconductive probe arms on or in the probe. Further, the conductive pathsmay extend from the base part to the cantilever part of the probe. Stillfurther, the plurality of conductive probe arms may be positioned at theouter planar surface. The outer planar surface may be any of thesurfaces, e.g. the one or more of the side surfaces of the cantileverpart, the bottom surface of the cantilever part or alternatively the topsurface of the cantilever part. Further alternatively the plurality ofconductive probe arms may be positioned/distributed at or on two or moresides, edges or surfaces at once.

The number of conductive probe arms may range from one to any number ofprobes possible to place on the cantilever part. The number ofconductive probe arms may be limited by the space occupied by theindividual conductive probe arm and the space available at the surfaceor edge of the cantilever part. As mentioned above, the conductive probearms may be positioned all at one side or in any distribution among thesides. Embodiments having 2 or more probe arms are contemplated to beadvantageous.

In an embodiment including more than 4 probe arms, any combination of 4probe arms may be used to perform 4-point measurements. There is notgiven any preference to embodiments having even or odd number of probearms. Generally, the co-operating testing machine may be able to addressone, more or all of the conductive probe arms simultaneously. Preferablythe testing machine may address any number of the conductive probe arms.

According to a sixth feature of the present invention, the first widthmay be 50 to 800 micron, such as 75 to 750 micron, such as 75 to 500micron, such as 80 to 350 micron, such as 85 to 250 micron, such as 90to 150 micron, such as 60 to 90 micron, such as 90 to 110 micron, suchas 110 to 190 micron, such as 190 to 240 micron, such as 240 to 290micron, such as 290 to 340 micron, such as 340 to 440 micron, such as440 to 550 micron, such as 550 to 650 micron, such as 650 to 800 micron,preferably 100 micron.

According to a seventh feature of the present invention, the secondwidth may be 40 to 300 micron, such as 50 to 250, such as 75 to 200micron, such as 100 to 175 micron, such as 120 to 150, such as 40 to 80micron, such as 80 to 120 micron, such as 120 to 160 micron, such as 160to 200 micron, such as 200 to 230 micron, such as 230 to 280 micron,such as 280 to 300 micron.

According to an eighth feature of the present invention, the first widthmay be 0.1 cm to 6 cm, such as 1 cm to 5.5 cm, such as 1.5 cm to 5 cm,such as 2 cm to 4.5 cm, such as 2.5 cm to 4 cm, such as 3 cm to 3.5 cm,such as 0.1 cm to 0.5 cm, such as 0.5 cm to 1 cm, such as 1 cm to 1.5cm, such as 1.5 to 2 cm, such as 2 cm to 2.5 cm, such as 2.5 cm to 3 cm,such as 3 cm to 3.5 cm, such as 3.5 cm to 4 cm, such as 4 cm to 4.5 cm,such as 4.5 to 5 cm, such as 5 cm to 5.5 cm, such 5.5 cm to 6 cm. Also,the first width may be greater that 6 cm or smaller than 0.1 cm.

According to an ninth feature of the present invention, the second widthmay be 0.1 cm to 6 cm, such as 1 cm to 5.5 cm, such as 1.5 cm to 5 cm,such as 2 cm to 4.5 cm, such as 2.5 cm to 4 cm, such as 3 cm to 3.5 cm,such as 0.1 cm to 0.5 cm, such as 0.5 cm to 1 cm, such as 1 cm to 1.5cm, such as 1.5 to 2 cm, such as 2 cm to 2.5 cm, such as 2.5 cm to 3 cm,such as 3 cm to 3.5 cm, such as 3.5 cm to 4 cm, such as 4 cm to 4.5 cm,such as 4.5 to 5 cm, such as 5 cm to 5.5 cm, such 5.5 cm to 6 cm. Also,the second width may be greater that 6 cm or smaller than 0.1 cm.

A probe implemented according to the eight and ninth features of thepresent invention may be useful when testing electrical properties ofwafers comprising a number of electrical components such as transistors.

A tenth feature of the present invention relates to the cantilever parthaving rounded edges or corners at the distal end. This is contemplatedto enable the cantilever to achieve a better alignment with thesubstrate on which electrical properties are to be measured.

According to a second aspect of the present invention a testingapparatus for testing electric properties on a specific location of atest sample is provided. The testing apparatus may comprise:

-   -   (a) means for receiving and supporting the test sample;    -   (b) electric properties testing means including electric        generator means for generating test signal and electric        measuring means for detecting a measuring signal;    -   (c) a probe for testing electric properties on a specific        location of a test sample, comprising:        -   1. a supporting body defining opposite first and second            parts constituting a flexible cantilever part predominantly            being flexible in one direction and a base part            respectively, the cantilever part defining an outer planar            surface substantially perpendicular to the one direction,            the base part being adapted for being fixated in a            co-operating testing machine,        -   2. at least one conductive probe arm in the cantilever part,            each of the at least one conductive probe arm being            positioned opposite the base part,        -   3. the cantilever part defining opposite first and second            regions, the second region being in contact with the base            part, the first region defining first and second side            surfaces, each of the first and second side surfaces            defining a first angle with the outer planar surface, a            first width defined between the first and the second side            surfaces, the second region defining third and fourth side            surfaces, each of the third and fourth side surfaces            defining a second angle with the outer planar surface, a            second width defined between the third and the fourth side            surfaces,        -   4. the second width being equal to or smaller that the first            width    -   (d) reciprocating means for moving the probe relative the test        sample so as to cause the conductive probe arms to be contacted        with the specific location of the test sample for performing the        testing of electric properties thereof.

The testing apparatus according to the second aspect of the presentinvention basically includes a point probe according to the first aspectof the present invention, which probe, constituting a component of thepoint testing apparatus according to second aspect of the presentinvention, may be implemented in accordance with any of the abovefeatures of the probe according to the first aspect of the presentinvention. Furthermore, in the testing apparatus according to the secondaspect of the present invention the electric properties testing meansmay further comprise means for electric properties probing of the testsample.

According to the teachings of the present invention the reciprocatingmeans may further comprise holding means adapted for co-operativelyreceiving the base part of the probe. Also the testing apparatus mayfurther comprise means for positioning the holding means across the testsample and recording of a location of the holding means relative to thetest sample.

The means for positioning may advantageously be maneuverable in allspatial directions, being directions coplanar to the test sample anddirections perpendicular to the test sample.

Further advantageously the means for positioning may further comprisemeans for angular movement of the holding means, so as to provideangular positions for the means for the probe. Even further, the meansfor positioning may further comprise means for angular movement of theholding means along an axis parallel to surface of the test sample, suchas to provide angular positions for the means for the probe. Stillfurther the means for positioning may even further comprise means forangular movement of the holding means along an axis perpendicular tosurface of the test sample, such as to provide angular positions for themeans for the probe.

According to a eleventh feature of the present invention the means forpositioning further comprising means for sensing contact between thetest sample and the means for the probe.

Most advantageously the probe according to the second aspect of thepresent invention may further include any of the features mentioned inrelation to the first aspect of the present invention.

Traditionally, probes are glued onto an aluminum, or aluminum oxide,substrate, a process that contains a certain amount of alignment errorby means of tilt and rotation of the probe before and during the curingof the glue. An angular uncertainty of 1˜2° is sufficient to compromisethe measuring quality. However, a substrate is necessary to support theprobe in the measuring head. Here, a self-aligning substrate that isintegrated in the measuring head as a semi-permanent part is to bedescribed.

In a crystalline structure, a co-ordinate system may be defined fordescribing the crystalline orientation of the molecules. Commonly, theaxis of a co-ordinate system of this sort is denoted l, h and K.

The crystallographic directions are also used to specify physicaldirections in the material. A direction parallel with a I-axis isdenoted by means of square brackets: [001]. All the directions that areparallel with one and only one crystallographic axis are then denoted<100>, i.e. using regular brackets denotes the family of symmetricallyequivalent directions, which have the same relationship towards a set ofcrystallographic axes but where the actual direction does not need to bespecified.

Semiconductors are a group of materials having conductivities betweenthose of metals and insulators. The atoms of the semiconductor materialswhen in solid state are arranged in crystal structures. The crystalstructures may be characterised by a unit cell. The crystal structure ischaracterized by a 3-dimensional periodicity which can be realized byseveral different geometries illustrated by a unit cell. The unit cellis a small volume which is repeated throughout the material at specificintervals. The unit cell may have any of a number of geometries such ascubic or non-cubic, such as tetragonal, orthorhombic, monoclinic,triclinic, hexagonal, rhombohedral or any other geometry. The geometryof the unit cells is described in the literature.

Silicon is arranged in a diamond crystal structure with 8 atoms per unitcell. Other physical properties include a melting point of 1415° C. anda density of 2.3 g per cm³.

Silicon may be readily oxidized at high temperature forming very stable,robust oxides that are highly resistant to almost all anisotropicetchings. Silicon dioxide may therefore be easily used as an almostperfect and inexpensive masking material. A vast variety of differentmicromechanical structures may be obtained using combinations ofdifferent parameters such as mask design, orientation of the mask withrespect to different crystallographic directions, the orientation of thecrystal of the starting silicon wafer, the level of doping using boronimpurities, and composition of concentration of etching solution and thetime used for the etching.

The diamond cubic structure of the silicon may be described as twointerpenetrating face-centered cubes displaced from each other along theX, Y and Z axes for ¼ of the latter spacing, i.e. the length of the unitcell.

The atoms in solid Ge is arranged in a crystal structure almostidentical to Si. Also ⅗ semiconductors, such as GaAs or Zinc blende hasthe same crystal structure as Si.

When etching the silicon material, several different types of solutionsexist, such as etching using EDP, KOH, NaOH and LiOH etching solutionswhere KOH is the most popular and commonly used etchant. A typicaletching rate for KOH with the silicon crystal planes far away from {111}plane are about 1 μm per minute. To the KOH solution, isopropyl alcoholmay be added as an addition of isopropyl alcohol is meant to decreasethe edge rate.

For masking purposes, generally any slow etching material in a specifiedetching solution may be applied as a mask. Both dielectrics and metalsmay serve as masking materials for anisotropic silicon etching such assilicon oxide, silicon nitrite, gold, chromium, silver or the like.

The idea behind the self-alignment is to exploit the nature of the{111}-planes of silicon. Since the sidewalls of the probe are 100% welldefined with respect to each other, these sidewalls will fit perfectlyinto a grave that has the same angling of its sidewall. By means ofKOH-etching in a silicon {100}-wafer, a grave with an outline that fitsexactly to the imprint of the bottom of a probe may be produced. Thisgrave will be referred to as a probe receptacle or recess.

According to a third aspect of the present invention, a method forproviding alignment of a probe relative to a supporting substrate isprovided. The method may comprise the steps of:

-   -   providing the supporting substrate defining a planar surface and        an edge, the substrate defining a first crystal plane,    -   providing a first mask at the surface of the supporting        substrate, the first mask defining a first exposed area on the        surface at the edge,    -   providing a specific etch reagent, the recess formed by the etch        reagent etching the first exposed area, the recess defining a        first sidewall an opposing second sidewall, an end wall remote        from the edge, and a bottom wall,    -   providing a probe substrate defining a planar surface and a        second crystal plane identical to the first crystal plane, using        the specific etch reagent so that the probe defines congruent        surfaces to the first sidewall and the second sidewall,    -   positioning the probe substrate so that the first and the second        crystal planes are positioned identically.

The supporting substrate and the probe substrate are in the presentlypreferred embodiment of the present invention made from identicalmaterials. However, different materials having identical crystalstructure may be used. The orientation of the crystal planes duringetching has an impact on the resulting structure. E.g. the speed of theetching will be different when etching in different angles or directionto the crystal structure. It is preferable to use a specific etchreagent in a specific direction to given material having a specificcrystal structure.

Provided the etching have been performed in identical direction inrelation to the crystal structure, the recess and the probe will haveside walls that will enable the probe to be positioned within the recessin an appropriate manner. The side walls of the recess will define afirst specific angle with the top surface of the supporting substrate.The side walls of the probe will define a second specific angle with thetop surface of the probe. Provided the supporting substrate and theprobe substrate both define substantially planar surfaces, the first andthe second specific angle will be supplementary angles. The sidewalls ofthe recess and the sidewalls of the probe will be parallel two and two,i.e. the sidewalls that are to be in facial contact, when the probe isreceived in the recess, will be parallel. A special combination ofmaterial having a specific crystal structure and using a specific etchreagent gives the desired structure of the recess in the supportsubstrate and the probe, thereby ensuring that the surfaces of therecess and the probe substrate are congruent or matching, so that theprobe will fit perfectly in the recess.

The probe used in relation to the third aspect of the present inventionmay include any of the features of the probe according to the firstaspect of the present invention. Also, the testing apparatus accordingto the second aspect of the present invention may include any of thefeatures of the probe supporting substrate of the third aspect of thepresent invention.

According to a twelfth feature of the present invention, the specificetch reagent may be provided at a specific concentration. Theconcentration of the etch-reagent may have an influence on the formationof the recess the probe.

According to a thirteenth feature of the present invention, a specifictemperature at which the etching is performed may be provided. Thetemperature at which the etch-reagent is exposed to the substrates mayhave an influence on the formation of the recess the probe. Also, aspecific pressure at which the etching is performed may have aninfluence on the formation of the recess the probe. Further, thespecific etch reagent the temperature the specific pressure may beapplied for a specific period of time. The period of time, for which theprobe and supporting substrates are exposed to the reagent, thetemperature the pressure, respectively, may have an influence on theformation of the recess and/or the probe.

According to the teachings of the present invention, the material usedto form the probe the supporting substrate may be Si, GaAs, any othersemiconductor material, combinations thereof, or any other singlecrystalline material with anisotropic etching properties similar tothose of semiconductor materials.

According to a fourteenth feature of the present invention, a secondmask may be provided at the bottom wall. The second mask may define asecond exposed area, a protruding area formed in the bottom surface byetching the second exposed area using the specific etch reagent. Also, asecond specific etching reagent may be employed.

A fifteenth feature of the present invention relates to the protrudingarea that may define a cross-section having a substantially square,rectangular, triangular, truncated pyramid, polygonal, semi-circular,partly circular, semi-elliptical, partly elliptical geometry or anycombinations thereof.

According to the teachings of the present invention, the method of thethird aspect may further comprise providing at least one conducting areain the first sidewall said second sidewall said end wall or anycombinations thereof.

The conducting area, pad or electrode is contemplated to establishelectrical contact to/from the probes to a measuring machine orapparatus by establishing electrical contact between conductive paths onthe probe and conductive paths on the supporting substrate or holder ofthe probe. This may be improved by further providing extensions of theat least one conducting area onto the planar surface.

A sixteenth feature relates to positioning the probe in alignment withthe recess in accordance with the third aspect of the present invention.

The supporting substrate may have one or more electrically conductivepaths formed in or on the surface of the substrate any or all of thesidewalls and/or the end wall, for establishing electrical connection tothe probe. Alternatively, the electrical connection may be establishedby bonding wires directly to pads on the surface of the probe it self.

According to a fourth aspect of the present invention, an apparatus forproviding alignment of a probe relative to a supporting substrate isprovided. The apparatus may comprise:

-   -   the supporting substrate defining a surface and an edge, the        supporting substrate defining a first crystal plane,    -   a recess formed by a specific etch reagent in the surface at the        edge of the supporting substrate, the recess defining a first        sidewall an opposing second sidewall, an end wall remote from        the edge, and a bottom wall,    -   a probe formed from a probe substrate defining a surface and a        second crystal plane identical to the first crystal plane using        the specific etch reagent so that the probe defines congruent        surfaces to the first sidewall and the second sidewall, the        probe is positioned in the recess.

According to the teachings of the present invention, the probe used inthe apparatus according to the fourth aspect, may include any of thefeatures of the probe according to the first aspect of the presentinvention.

According to a seventeenth feature of the present invention, the bottomwall may include a protruding part and the probe may include aco-operating groove. Further, the protruding part may define asubstantially square, rectangular, triangular, truncated pyramid,polygonal, semi-circular, partly circular, semi-elliptical, partlyelliptical cross-section or any combinations thereof.

According to an eighteenth feature of the present invention, theprotruding part may extend from the first side wall to the second sidewall. Alternatively, the protruding part may extend from the first sidewall to the end wall; further alternatively, the protruding part mayextend from the second side wall to the end wall. Even furtheralternatively, two or more protruding parts may be included in therecess.

According to a nineteenth feature of the present invention, thesupporting substrate may further include at least one substratealignment mark and the probe includes at least one corresponding probealignment mark. The alignment mark may be used for visually inspectingthat the probe has been positioned correctly in the recess of thesupporting substrate. Also, the alignment marks may be used by a machinewhile positioning the probe in the recess. Particularly, the substratealignment mark the probe alignment mark may be constituted by an etchedalignment recess alignment protruding part.

According to a fifth aspect of the present invention, a testingapparatus for testing electric properties on a specific location of atest sample is provided. The testing apparatus may comprise:

-   -   means for receiving and supporting the test sample;    -   electric properties testing means including electric generator        means for generating a test signal and electric measuring means        for detecting a measuring signal;    -   a probe for testing electric properties on a specific location        of a test sample, the probe received in an apparatus for        providing alignment of the probe relative to a supporting        substrate, the apparatus comprising:    -   the supporting substrate defining a surface and an edge, the        substrate defining a first crystal plane,    -   a recess formed by a specific etch reagent in the surface at the        edge of the supporting substrate, the recess defining a first        sidewall an opposing second sidewall, an end wall remote from        the edge, and a bottom wall defining a minimum height from the        surface,    -   the probe formed from a probe substrate defining a surface and a        second crystal plane identical to the first crystal plane using        the specific etch reagent so that the probe defines congruent        surfaces to the first sidewall and the second sidewall, the        probe received in the recess,    -   reciprocating means for moving the probe relative the test        sample so as to cause one or more conductive probe arms        positioned on the probe to be contacted with the specific        location of the test sample for performing the testing of        electric properties thereof.

The apparatus according to the fifth aspect of the present invention maycomprise any of the features produced by performing any of the stepsaccording to the second, third or fourth aspect of the presentinvention. Also, the testing apparatus according to the second aspect ofthe present invention may include any of the features of the fourth andfifth aspect of the present invention.

A sixth aspect of the present invention relates to a method for testingelectrical properties. The method comprises:

-   -   i) providing a test sample defining a first surface, an area        defined on the first surface,    -   ii) providing a first test probe comprising:        -   a first plurality of probe arms each including at least one            electrode for contacting a respective location on the test            sample,    -   iii) providing a second test probe comprising:        -   at least one probe arm including at least one electrode for            contacting a location on the test sample,    -   iv) providing a test apparatus including a first and a second        holder for receiving the first and the second test probes        respectively, each of the holders comprising positioning devices        for positioning relocating each of the holders in three        dimensions, the test apparatus being electrically connected to        each of the electrodes of the first test probe and to the at        least one electrode of the second test probe, the test apparatus        further comprising a sample holder for receiving and holding the        test sample in a specific orientation relative to the first and        the second test probe,    -   v) positioning the electrodes of the probe arms of the first        test probe in contact with the area,    -   vi) positioning the at least one electrode of the at least one        probe arm of the second test probe in contact with the area at a        location remote from the first test probe,    -   vii) transmitting a test signal from at least one of the        electrodes of the first test probe, or, in the alternative from        the at least one electrode of the second test probe, and    -   detecting the test signal transmission between the first and the        second test probe.

Additionally, the method according to the sixth aspect may furthercomprise intermediate steps after step vi):

-   -   a) providing a magnetic field generator for generating a        magnetic field,    -   b) positioning the magnetic field generator so that the field        lines of the magnetic field defines a specific orientation with        the area of the test sample.

The method according to the sixth aspect of the present invention mayfurther comprise the steps of:

-   -   c) relocating or moving the first test probe relative to the        area and/or relocating or moving the second test probe relative        to the area, and    -   d) repeating step vii) the intermediate steps a) b).

The movement of either one or both of the test probes is contemplated toallow for investigations of electrical properties of a greater area ofthe test sample, as there may be localized variations.

Moving both of the probes in the same direction and with the same speed,thereby maintaining a specific distance and orientation between the two,or more, test probes, is also possible.

The measurements may be performed while the test probes are moved;alternatively, the test probes are moved and then stopped beforemeasurements are performed.

The present invention relates to a seventh aspect to a method fortesting electrical properties, the method comprises:

-   -   i) providing a test sample defining a first surface, an area        defined on the first surface,    -   ii) providing a first test probe comprising:        -   a first plurality of probe arms each including at least one            electrode for contacting a respective location on the test            sample,    -   iii) providing a second test probe comprising:        -   at least one probe arm including at least one electrode for            contacting a location on the test sample,    -   iv) providing a test apparatus including a first and a second        holder for receiving the first and the second test probes        respectively, each of the holders comprising positioning devices        for positioning and/or relocating each of the holders in three        dimensions, the test apparatus being electrically connected to        each of the electrodes of the first test probe and to the at        least one electrode of the second test probe, the test apparatus        further comprising a sample holder for receiving and holding the        test sample in a specific orientation relative to the first and        the second test probe,    -   v) positioning the electrodes of the probe arms of the first        test probe in contact with the area,    -   vi) positioning the at least one electrode of the at least one        probe arm of the second test probe in contact with the area at a        location remote from the first test probe,    -   vii) providing a magnetic field generator for generating a        magnetic field,    -   viii) positioning the magnetic field generator so that the field        lines of the magnetic field defines a specific orientation with        the area of the test sample, and    -   ix) detecting electrical signals at the first and/or the second        test probes.

Additionally, the method according to the seventh aspect may furthercomprise the steps of:

-   -   a) transmitting a test signal from at least one of the        electrodes of the first test probe, or, in the alternative from        the at least one electrode of the second test probe, and    -   b) detecting the test signal transmission between the first and        the second test probe.

Furthermore, the method according to the seventh aspect may eventfurther comprise the steps of:

-   -   c) relocating or moving the first test probe relative to the        area and/or relocating or moving the second test probe relative        to the area, and    -   d) repeating step ix) the steps a) b).

The magnetic field may be generated by a permanent magnet, anelectro-magnet, a coil or alternatively by any other device capable ofgenerating a magnetic field. The magnetic field may be substantiallyconstant, varying or a combination hereof.

The magnetic field source or generator preferably generates a magneticfield that defines a specific orientation with the area defined on thetest sample. The orientation may be orthogonal, tilted or angled.

The magnetic field generator may be in a fixed location or be placed ina holder including positioning devices or means, such as actuators orthe like.

The mentioned test sample is preferably a semiconductor device, such asan ASIC, a FPGA, a SOC or any other device of which the testing,diagnosing, detection or registration of electrical properties are to beperformed.

The first test probe preferably has four probe arms each including atleast one electrode; however, the test probe may have one, two, three,five, six, eight, twelve, fourteen or any other positive integer, numberof probe arms. The probe arms are preferably

The second test probe may include only one probe arm or more probe arms,such as four. The second test probe is preferably similar to the firsttest probe, i.e. in all of the physical dimensions, geometry etc. Thesecond test probe may comprise a plurality of probe arms each comprisingat least one electrode.

The test apparatus may include a housing in which the differentcomponents are placed or mounted. The housing may additionally provide achamber in which the testing is performed. The chamber may provide thepossibility of, or means for, controlling and monitoring the conditionsunder which the testing is performed, such as pressure, composition ofair/atmosphere, temperature, vacuum or in vacuo conditions, moisture orany combinations thereof.

The holders in the test apparatus are moved by the positioning-devices,which preferably are constituted by piezo-electrical actuators, or anyother actuators allowing control of the holders in sub-micronresolution.

The test probes are positioned so that at least one of the probe arms ofeach of the test probes are in contact with the test sample at at leasttwo locations at some distance. The distance may be in the micron rangeor less; also, the distance may be greater.

A test signal may be applied to at least one of the electrodes from asignal generator via electrical connections on or in the test probe.Alternatively, the test signal is generated transmitted through or fromthe test-sample, e.g. via signal paths in or on the test-sample. This iscontemplated to enable electrical-property tests, circuit tests andother tests.

The test signal may be constituted by an AC signal, a DC signal, a HFsignal or any combination thereof. The test apparatus preferablyincludes detection devices for detecting the transmission of the testsignal through the test sample. The detection may be recorded ordetected and then sent to signal processors for obtaining more detailedinformation regarding the electrical properties of the test sample.

According to the teachings of the present invention, a multitude ofelectrode pads may be defined on the surface of the test sample and themethod may further comprise bringing a first specific electrode incontact with a second specific electrode pad, bringing a third specificelectrode in contact with a fourth specific electrode pad,

-   -   transmitting a test signal from the first or the third specific        electrode, and    -   detecting the test signal transmission between the third or the        first electrode, respectively.

The determination of the location of the electrode pads may be performedby visual inspection by moving a test probe until electrical tests showthat contact with an electrode pad has been achieved.

The probe arms of the first test probe are, preferably, substantiallyparallel and the at least one probe arm of the second defines alongitudinal length. The probe arms preferably extend from a bodyforming a base part of the test probe, such as discussed in relationwith the first to fifth aspect of the present invention. The test probesused in relation with the sixth aspect of the present invention, mayincorporate any or all of the features of the probes and/or methodsaccording to any of the first to fifth aspects of the present invention.

As the probe arms of each of the test probes may define a direction orlength, arranging two or more of these test probes may result in severalpossible configurations.

Therefore, the method according to the sixth and/or seventh aspect ofthe present invention may further comprise:

-   -   arranging the first and the second test probes so that the probe        arms of the first test probe are substantially parallel with the        at least one probe arm of the second test probe, or    -   arranging the first and the second test probes so that the probe        arms of the first test probe are in an orientation substantially        orthogonal with the at least one probe arm of the second test        probe.

Alternatively, any other angle between the probe arms of the test probesmay be obtained, within the ranging from 0 to 360 degrees.

Specifically, at least one additional test probe comprising at least oneprobe arm including at least one electrode for contacting a location onthe test sample, may be provied, and the method may the comprise:

-   -   providing at least one additional holder in the test apparatus        for receiving and holding the at least one additional test        probe.

The at least one probe arm of the at least one additional test probe maydefine a longitudinal length. The method according to the sixth seventhaspect of the present invention may further comprise:

-   -   arranging the first, the second and the at least one additional        test probe in a arrangement where the probe arms of the first        probe define a first angle with the at least one probe arm of        the second test probe, and the probe arms of the first probe        define a second angle with the one probe arm of the at least one        additional test probe.

The first and second angles may be identical, i.e. the angles may be 120degrees, or the first and second angle may be different.

The methods according to the sixth and seventh aspects of the presentinvention may incorporate any of the features of any of the aspects oneto five or six of the present invention.

According to an eighth aspect of the present invention, an apparatus fortesting electrical properties comprises:

-   -   a housing,    -   a first and a second holder for receiving a first and a second        test probe, respectively, mounted in the housing, each of the        holders comprising positioning devices for positioning        relocating each of the holders in three dimensions,    -   the first test probe comprising:        -   a first plurality of probe arms each including at least one            electrode for contacting a respective location on the test            sample,    -   the second test probe comprising:        -   at least one probe arm including at least one electrode for            contacting a location on the test sample,    -   the test apparatus electrically connected to each of the        electrodes of the first test probe and to the at least one        electrode of the second test probe, the test apparatus further        comprising a sample holder for receiving and holding a test        sample in a specific orientation relative to the first and the        second test probe, the test sample defining a first surface, an        area defined on the first surface,    -   a signal generator for generating a test signal electrically        connected to a transmitter device for transmitting the test        signal via at least one of the electrodes of the first test        probe in contact with the area, or, in the alternative, via the        at least one electrode of the second test probe in contact with        the area, and    -   a detection device for detecting the test signal transmission        between the first and the second test probe.

Furthermore, the positioning-devices of the apparatus may be constitutedby piezo-electrical actuators, alternatively by any other devicesproviding sufficient spatial movement resolution. Sufficient spatialmovement resolution is preferably in the micron or sub-micron range,possibly even smaller ranges.

The probe arms of the first test probe may be substantially parallel andthe at least one probe arm of the second may define a longitudinallength,

-   -   the first and the second test probes may be arranged so that the        probe arms of the first test probe are substantially parallel        with the at least one probe arm of the second probe arm, or    -   the first and the second test probes may be arranged so that the        probe arms of the first test probe are in an orientation        substantially orthogonal with the at least one probe arm of the        second probe arm.

Advantageously, the apparatus may further comprise:

-   -   at least one additional test probe comprising:        -   at least one probe arm including at least one electrode for            contacting a location on the test sample,    -   and    -   at least one additional holder in the housing of the test        apparatus for receiving and holding the at least one additional        test probe.

Also, the at least one probe arm of the at least one additional testprobe may define a longitudinal length, the apparatus may furthercomprise:

-   -   the first, the second and the at least one additional test probe        arranged in an arrangement where the probe arms of the first        probe define a first angle with the at least one probe arm of        the second test probe, and the probe arms of the first probe        define a second angle with the one probe arm of the at least one        additional test probe.

The apparatus according to the eighth aspect of the present inventionmay incorporate any of the features of any of the aspects one to sevenof the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned objects, advantages and features, will be evident,along with numerous other objects, advantages and features, from thedetailed description below, where

FIG. 1 is a schematic illustration of a probe according to the presentinvention,

FIG. 2 is an enlarged view of a part of an alternative embodiment of aprobe according to the present invention,

FIG. 3 a-3 c are schematic views of cross-sections of probes accordingto the present invention,

FIG. 4 is a schematic view of a part of a probe according to the presentinvention,

FIG. 5 is a schematic illustration of a substrate,

FIG. 5 a is a schematic, zoomed view of a part of the substrate of FIG.5,

FIG. 5 b is a schematic, zoomed, cross-sectional view of a part of thesubstrate illustrated in FIG. 5.

FIG. 6 is a schematic view of two supporting substrates,

FIG. 7 is a schematic view of a wafer comprising a number of supportingsubstrates,

FIG. 8 is a schematic illustration of a probe and a supporting substrateincluding a recess,

FIG. 9 is a schematic top view illustrating the probe and supportingsubstrate of FIG. 8,

FIG. 10 is a schematic view of a probe mounted in a measuring set-up,

FIG. 11 is a schematic view of a probe mounted in the measuring set-upof FIG. 10,

FIG. 12 is a schematic view of a substrate and a recess includingelectrical conductive paths,

FIG. 13 is a schematic view of a substrate and a recess including aprotruding part,

FIGS. 14 a to 14 d are schematic view of a test configuration comprisingtwo multi point probes including movement,

FIG. 15 is a schematic view of a test configuration comprising twomulti-point probes, and

FIG. 16 is a schematic view of a different test configuration comprisingtwo multi-point probes, and

FIGS. 17-25 are schematic views of alternative embodiments of probes.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic illustration of a probe 10 for testing electricproperties on a specific location of a test sample. The probe bodycomprises two parts, 12 and 14, constituting a base part and a flexiblecantilever part respectively. The flexible cantilever part 14 comprisestwo regions, a distal region 16 and a connection region 18. Theconnection region 18 connects the cantilever part 14 with the base part12.

In the presently preferred embodiment of the present invention thedistal region 16 further comprises a plurality of conductive probe arms,not illustrated, for testing the electrical properties of a specificarea on a test sample, also not illustrated. The conductive probe armspreferably extend from the top surface of the distal region 16.Alternatively, the conductive probe arms is positioned at one or more ofthe side surfaces 20 top 22 bottom 24 surfaces of the distal region 16.

For establishing electrical contact to a testing apparatus, the probebase 12 may include electrical connection pads 26, for establishing theelectrical connections to the electrical conductive paths 28, thatfurther establishes the electrical connections to the conductive probearms.

The connection region 18 may comprise one or more areas where some ofthe material used to form the probe body have been removed. These areasmay be constituted by one or more apertures, holes or indentations 30.The apertures 30 in FIG. 1 are illustrated as oblong apertures; howeveraccording to the teachings of the present invention, the apertures mayhave any geometrical configuration, such as round, square, oblong,elliptical, triangular or any polygonal geometry or combinationsthereof.

The areas 30 need not be through going holes, but may be indentations,notches, depressions, dents, grooves, recesses, dimples or anycombinations thereof.

Also, the connection region 18 may include areas where some of thematerial has been removed from the outside, such as the regiondesignated 32 in FIG. 1. The connection region 18 may have acorresponding region on the side not illustrated in FIG. 1. The region32 illustrated in FIG. 1 has a substantially flat surface that isperpendicular to the substantially flat surface of the connection region18. However, the region 32 or a part hereof, may define an angle inrelation to the surface of the connection region 18 different than 90degrees, such as 45 degrees.

Part 35 of the side or bottom of the connection region 18 may define adifferent width than other parts of the connection region 18, such asthe region 32. This thinner area enables the cantilever 14 to achieve ahigh degree of flexibility.

The connection region 18 and the distal part 16 may be interconnected byregions 36, 38. The regions 36, 38 may provide a better stability of thecantilever probe, but may also be omitted.

The base part 12 is preferably formed so as to fit into a co-operatingreceiving recess in a holder device, or the like, in a testing machine.When the probe 10 is positioned in a holder electrical connections maybe established thereto via the pads 26.

FIG. 2 is a zoomed view of the connection region 18 and the distalregion 16 of an alternative embodiment the probe 10. Here an improvedflexibility of the cantilever part 14 of the probe 10 is achieved byremoving a part of the material across the connection region 18. In theembodiment illustrated in FIG. 2, the cut-out 40 has atruncated-triangular cross-section. Other possible cross-sections areillustrated in FIGS. 3 a-3 c. In FIG. 2 all of the electrical pathwaysare omitted from the illustration.

In both the embodiment illustrated in FIG. 1 and the embodimentillustrated FIG. 2 the number of apertures 30 is three; however, thenumber of apertures may be varied, from zero to as may as possible. Theimproved flexibility may be achieved by any of the means describedabove, i.e. one or more attenuated or thinned areas and/or one or moreapertures.

The distal end of the cantilever part of the probe has in one cornerbeen illustrated as having an angled surface and in the opposite cornera non-angled surface is illustrated. The presence or non-presence of anangled surface depends on the method used for producing probe, i.e. theetching and the etching solution.

In FIG. 3 a a cross-section of a probe according to the presentinvention is illustrated. The probe 10 may at any surface include anindentation or cut-away area. The indentation or cut-away area mayconstitute the area 40 illustrated in FIG. 2, or be included in any ofthe surfaces of connection region 18, i.e. any of the side surfaces ortop and/or bottom surfaces, also in any combinations thereof.

FIG. 3 a specifically illustrates an area having a discontinuousindentation 42 in the surface 50, with a specific angle defined betweenthe sidewalls 44, 46. The surface 48 opposite the surface 50 may alsoinclude an indentation.

FIG. 3 b illustrates a surface 54 having a continuous indentation 52.The indentation 52 may have a hyperbolic or a semi-circularcross-section. The surface 56 opposite the surface 54 may also includean indentation.

FIG. 3 c illustrates a surface 58 including an indentation or trench 62defined by two sidewalls 64,68 and a bottom wall 66. The two sidewalls64, 68 define an angle between the two walls. The overall geometry ofthe trench may be substantially a truncated triangular. Provided thesidewalls 64,68 are substantially parallel, the trench will define asubstantially square or oblong cross-section.

FIG. 4 illustrates a cross-section where two opposite surfaces 70, 72both include indentations 74 and 76, here illustrated as having asubstantially rounded bottom. Any surface may include one or moreindentations, trenches or cut-away areas.

A method for producing probes in SiO₂ according to the present inventionmay comprise the following sequence of steps:

-   a) Validation and thickness adjustment of the wafer,-   b) Wet thermal wafer oxidation at 900-950° C.-   c) Front side lithography of silicon oxide pattern-   d) Silicon oxide etch (anisotropic Reactive lonbeam Etch (RIE))-   e) Front side lithography of trench notch pattern-   f)silicon trench etching (Deep RIE)-   g) Low stress silicon nitride deposition (LPCVD)-   h) Back side lithography (backside alignment)-   i) Backside silicon nitride etch (anisotropic RIE)-   j) HF etch through back side silicon oxide-   k) Wet silicon etch (KOH)-   l) Front side silicon nitride etch (anisopropic RIE)-   m) Front side silicon etch (isotropic RIE)-   n) Metal evaporation (e-beam; static mode)

An attenuation or thinning of the cantilever or connection area may beperformed between step m and n in a deep reactive ionbeam etch, (DRIE)process.

A method for producing probes as SOI according to the present inventionmay comprise the following sequence of steps:

-   a) Low stress silicon nitride deposition (LPCVD)-   b) Front side lithography-   c) Front side silicon nitride etch (anisotropic etch)-   d) Back side lithography (Back side alignment)-   e) Back side silicon nitride etch (anisotropic RIE)-   f) HF etch through front and back side silicon oxide-   g) Wet silicon etch (KOH)-   h) SiO₂ etch (bHF)-   i) Front side silicon nitride etch (anisotropic RIE)-   j) Monocantilever thinning (Deep RIE)-   k) Electrode formation, e.g. metal evaporation and patterning.

The methods of producing the probes may be modified by persons skilledin the art.

In FIG. 5, orientation of a {100} surface 80 with respect tocrystallographic axes 82, 84, 86 is illustrated. Etching through a maskhole results in pyramidal shaped grooves 88 defined by the {111}-planesillustrated in FIGS. 5 a and 5 b in detail. The base plane of theinverted pyramid is defined by 4 line elements being parallel with two<110>-directions.

The base material used for the manufacturing may be silicon {100 }wafers. The digits in braces denote the orientation of the siliconsurface with respect to crystallographic axes. With silicon {100 } thewafer surface normally is parallel with one specific crystal axis. InFIG. 5, a wafer is shown together with the three axes h, k and I. Inthis example, the I-axis is normal to the wafer surface. The axes aredrawn outside the wafer for convenience, but it is important to realizethat this kind of co-ordinate system describes symmetry lines inside thematerial.

Surface planes defined by the crystallographic axes bound the material.Thus the front surface shown is the (001)-plane since it is normal tothe third axis. Due to symmetry, the second axis or the first axis mightbe chosen to point upwards, the front surface would in those cases bedenoted either a (010)-plane or a (100)-plane, respectively. Theparentheses are used to denote specific orientations of planes. Sinceall these three planes have equivalent symmetry, they are commonlydenoted {100}. The regular braces indicate a plane being a member ofplanes with the same crystal symmetry so that the {100}-planes arespecifically normal to crystal axis but that the actual sequence ofcrystal axes is arbitrary.

Various gaseous and liquid compounds can etch silicon. One of thesecompounds is concentrated, aqueous KOH. However, KOH does not etchequally well in all directions of silicon. The <100>-directions are easydirections, whereas <111 > are extremely slow directions. Now, since the{100}-planes and {111}-planes intercept along <110>-lines this has thefollowing consequence, If a silicon {100 } surface is covered with achemically resistant mask layer with some holes in it, KOH will only beable to attack a rectangular area bounded by the <110>-lines that framethe hole in the mask. As the KOH etches downwards along the<100>-direction it will be confined by {111}-planes that emerge at the<110>-lines on the front surface. Such an etched hole 88 is shown in thewafer in FIGS. 5, 5 a and 5 b. If the front outline of the hole isquadratic, a pyramidal shaped hole will result, The two groove sketchesshown in FIGS. 5 a and 5 b illustrate this. If the front outline israther rectangular, the same four {111}-planes will bound the etchedhole; however, one pair of oppositely oriented {111}-planes will becomeoblong resulting in a V-shaped oblong groove. If the mask hole issufficiently small compared with the wafer thickness, the KOH-etch willsimply stop once there are only {111}-planes left as shown in FIG. 5. Ifthe front hole is sufficiently large, the KOH may etch all way throughthe wafer.

Since the {111}-planes are defined by crystallographic axes, theirorientation with respect to the crystallographic axes are 100% welldefined. A {111}-plane makes an angle of 350.2° with the [001]-directionand thus with the wafer normal. This angle is a geometric fact, given bythe nature of the crystal symmetry.

An example of a multipoint probe has been described in detailspreviously. A number of freely suspended probe pins may be etched intosilicon dioxide on top of a silicon chip by means of traditional MEMSprocesses. The probe manufacturing process is summarized here becausecertain parts of it plays a decisive role in the subject of thisdescription, namely the self-alignment of the probe upon mounting in arecess.

The process sequence for probe manufacture is:

-   -   1. A double side polished silicon {100} wafer of a well-defined        thickness is covered with a 1 μm thick silicon dioxide layer.        This is done by wet thermal growth.    -   2. The front side is chosen. On the front side the probe pattern        is transferred to a photo resist layer with 1:1        photolithography. The pattern is aligned to the <110>-directions        precisely to within fractions of a degree.    -   3. The photo resist pattern is transferred to the front side        silicon dioxide by means of an anisotropic reactive ion etching.        Afterwards the photo resist is stripped.    -   4. The wafer is covered with a thin layer of low-stress silicon        nitride by means of low pressure chemical vapor deposition.    -   5. On the backside of the wafer, the backside pattern is        transferred to a photo resist layer with 1:1 photolithography.        This backside pattern is carefully aligned to the front side        pattern in a mask aligner. The backside pattern defines the        outline of the probe chips taking into account that the backside        outline and the front outline of the individual probes will        differ in size because of the consecutive KOH-etch that produces        35.2° angled side walls with respect to vertical, i. e.        {111}-planes.    -   6. The backside pattern is transferred to the silicon nitride        layer by means of an anisotropic reactive ion etching. The        silicon dioxide layer immediately below the holes in the silicon        nitride layer is etched away in a buffered hydrofluoric acid.    -   7. The wafer is etched in a warm, concentrated KOH-solution        under careful and constant stirring. The KOH etches entirely        through the wafer, thus defining the individual probe chips on        the wafer. Due to the highly anisotropic etch rates in silicon,        the chips get a characteristic “gold bar”-like shape.    -   8. The silicon nitride on the wafer front side is removed in a        reactive ion etch. Immediately afterwards, the front side        silicon is under-etched a few μm in an isotropic reactive ion        etch. This provides a certain isolation of the front side        pattern from the silicon base.    -   9. A gold layer of about 100 nm is deposited on the front side        of the wafer by means of a physical vapor deposition technique;        typically e-beam evaporation is chosen.

The probe may be a silicon chip having one or more freely extendingcantilevers that are electrically conducting and with spacings of a fewμm so that the probe may be used for making one- or multipointresistance measurements in the microscopic regime. In order to handlethe probe in a practical situation, it has to be mounted on a largersubstrate that has a high degree of mechanical stability. The substratefits mechanically into the measuring head, which contains the necessarycontacting and pre-amplification circuitry.

The idea behind the self-alignment is to exploit the nature of the{111}-planes of silicon. Since the sidewalls of the probe are 100% welldefined with respect to each other, these sidewalls are contemplated tofit perfectly into a grave that has the same angling of its sidewalls,i.e. by means of KOH-etching in a silicon {100}-wafer, we can make agrave with an outline that fits exactly to the imprint of the bottom ofa probe. This grave will be referred to as a probe receptacle.

The process sequence for substrate manufacture is:

-   -   A. A single side polished silicon {100} wafer of a well defined        thickness is covered with a thin layer of low stress silicon        nitride layer, typically 100-125 nm. This is done by means of        low-pressure chemical vapor deposition.    -   B. The front side of the wafer is covered with a positive photo        resist. On the front side the substrate pattern is transferred        to the photo resist layer using 1:1 photolithography. The        pattern is aligned to the <110>-directions precisely to within        fractions of a degree. The pattern layout is summarized in        FIG. 6. The layout in FIG. 6 defines a double set of substrates        104, 106. Every layout element within the white thin solid line        92 is repeated as a rectangular array throughout an area on the        photolithographic mask that corresponds to the available wafer        112 area. This is illustrated in FIG. 7. The photo resist is        illuminated in the black 94, 95, 100, 102, 108, 109, 110, 111        and chessboard-patterned rectangles 98. After development of the        photo resist, all white regions will be covered by photo resist.    -   C. The photo resist pattern is transferred to the front side        silicon nitride by means of an anisotropic reactive ion etching.        Afterwards the photo resist is stripped. At this stage, we have        acquired rectangular holes in the silicon nitride layer        corresponding to all the areas 94, 95, 100, 102, 108, 109, 110,        111 and rectangles 98 in FIG. 6.    -   D. The wafer is etched in an 80° C. warm, concentrated        KOH-solution under thorough and constant stirring. The KOH will        only attack those parts of the front side of the wafer that are        not covered with silicon nitride. This process is stopped, when        the KOH has etched entirely through the wafer in those pattern        elements that form the probe receptacles.    -   E. After rinsing and drying, the wafer has a grooved structure        defined by FIG. 6 (detail) and FIG. 7 (rectangular array of the        detail in FIG. 6). Now, the white area represents the wafer        front side. The rectangle 98 in FIG. 6 corresponds to a region,        where the KOH has etched entirely through the wafer. This region        98 defines the bottom of the receptacles of two semi-detached        probe substrates 104 and 106. The white dotted lines 96        represent the line segments where two neighboring {111}-planes        adjoin. With reference to FIG. 6 they will always adjoin along        vertical or horizontal lines at the bottom of a groove, whereas        the 45° angled lines always represent side edges of the groove.        The four quadratic etch pits 108, 109, 110 and 111 are used as        alignment marks. Also, the vertical rectangles do not have side        edges (45° lines). This is because these rectangles continue all        the way through the cell layout. In this way they will “melt        together” with the similar rectangles from the vertically        neighboring cells. The resulting vertical rectangles will extend        all the way through the layout to be terminated at the two        respective cells that define the vertical ends of the layout.    -   F. The wafer is easily broken into substrate wands by breaking        along the through-going vertical grooves 94. The wands are then        broken into individual substrates by breaking carefully along        the horizontal grooves 100 and/or 102. The overall way of        breaking is similar to the way in which you would break a        groove-patterned plate of chocolate into regularly formed        pieces. Alternatively, the wafer may be subdivided by techniques        commonly known as dicing.

FIG. 6 illustrates a detail of the pattern layout as seen from the frontside of the wafer. The entire pattern within the thin solid white linesis repeated vertically and horizontally in a rectangular array limitedby the wafer size as illustrated in FIG. 7. The black andchessboard-patterned rectangles represent the areas where the positivephoto resist is illuminated.

These regions will subsequently be etched in KOH. After KOH-etch, theblack areas 98 represent {111}-planes bounding the etch grooves. Theseplanes adjoin along the dotted lines 96. After KOH-etch, thechessboard-patterned rectangle 98 represents the bottom of two probereceptacles. This pair of probe substrates 104, 106 is turned into twoindividual substrates by breaking along a horizontal line parallel withthe two minor, horizontal grooves 100, 102 in the middle of the layout.The way of breaking is similar to the way in which you would break agroove-patterned plate of chocolate into regular pieces.

The edges of the final substrate are defined by nature's geometry. Thus,edges that are perpendicular to each other make angles of exactly 90.0°whereas edges that are parallel with each other are in fact trulyparallel. Consequently, the substrate can be fit exactly parallel withthe side edges of a matching slot in the measuring head.

FIG. 7 schematically illustrates the pattern layout from FIG. 6 repeated84 times and distributed on the available area of a 6″ wafer.

FIG. 8 is a schematic, perspective view of a probe 122 and a probesupporting substrate 114. In the probe supporting substrate 114 a recessis formed. The recess is defined by the back wall 116, the two sidewalls 118 and 120, and the bottom 119.

The side walls 118 and 120, along with the end wall 116 have been formedby etching with a specific etching reagent. The etching reagent may beKOH or another etch reagent.

The probe 122 includes side walls 124 and 128 and an end wall 126. Theside walls 124 and 128 define angles with the planar top surface of theprobe 122 that are supplementary with the angles that the side walls 118and 120 define with the top surface of the base 114 and similar with thebottom 119. As the angles are supplementary, the probe will align withthe substrate 114 when the probe is inserted or positioned in therecess. The probe 122 may be placed mechanically, i.e. by a precessionmachine, or by an automatic placement method.

At the end 130 remote from the end wall 126 of the probe 122, one ormore probe arms 132 may extend. The probe arms 132 may be used toperform measurements of electrical, and other, properties of testsamples.

The probe 122 may further comprise one or more pairs of alignment marks136 and 134, on the top surface of the probe 122. The alignment marksmay assist in verifying that the probe 122 is placed correctly in therecess. Corresponding alignment marks 138 and 140 may be formed, or byother means provided, in the top surface of the supporting substrate114.

FIG. 8 is a schematic illustration of a side view from above showing theself-alignment substrate and how to fit the probe down into thereceptacle. The right and the left sides of the substrate are bounded byedges that are strictly parallel to each other and also strictlyparallel to the probe-aligning receptacle, The backside of the substrateis mostly defined by an edge that is strictly perpendicular to the rightand left edges.

In FIG. 8 the substrate is illustrated from a side view slightly abovethe surface. The sidewalls 116, 118, 120 of the substrate are notvertical but define an angle of 35.20 with the vertical direction, dueto the crystalline structure of the material.

The front end of the substrate has four triangular facets 145 a, 145 b,145 c, 145 d. These facets 145 a, 145 b, 145 c, 145 d appear due tobreaking or dicing of the substrate pair in FIG. 6 into two halves andconsist of the silicon that will remain after etching of the grooves.The facets 145 a, 145 b, 145 c, 145 d may protrude a little, but this iscontemplated to have no significance.

In the middle of the substrate, the self-alignment groove, being theprobe receptacle, is illustrated. The two holes 138, 140 on each side ofthe probe receptacle near the front end of the substrate serve aspositional alignment marks.

In the top part of FIG. 8 the probe 122 is shown. The arrows indicatethe movement of the probe 122 down into the receptacle. A slightuncertainty in the positioning along the substrate front, i.e. along aline parallel with the wall 116, may be accepted. This is because as theprobe enters into receptacle it will eventually meet one of thesidewalls 118 or 120 of the receptacle. Pushing the probe 122 furtherdown will simultaneously force it sideways into alignment with theoutline of the receptacle.

In FIGS. 8 and 9 the electrical pathways on the probe surface areomitted and only the pads are illustrated.

A bottom wall 119 may be formed in the bottom of the recess orreceptacle depending on the thickness of the starting material, i.e. thesubstrate 114, and the time used for etching the recess. It ispreferable that the bottom of the probe is not in facial contact withthe bottom wall 119. In one embodiment of the recess, the bottom wall119 may be nonexistent, meaning that the recess is open in a downwarddirection in relation to the set-up of FIG. 8.

FIG. 9 is a schematic top view of the set-up of FIG. 8. The probe 122has been placed above the recess of the substrate 114. The back wall 126of the probe 122 is not in facial contact with the back wall 116 of thesubstrate 114. In alternative embodiments, the back wall 126 and theback wall 116 may be in facial contact. The bottom of the probe 122 isnot required to be in facial contact with the bottom wall 119 of therecess. Illustrated in FIG. 9 the “bottom” 119 is not present. Inalternative embodiments, the bottom 119 may be present depending on thethickness of the substrate 114 and the time used for etching the recess,and also on the concentration of the etchant. It is preferable that thebottom of the probe is not in facial contact with the bottom of therecess in the substrate.

The alignment marks 134 and 136 are positioned in alignment with thealignment marks 138 and 140 on the surface of the substrate 114.

The surfaces 144 and 146 have been formed by etching. The surfaces haveformed a recess constituting a weakening of the wafer from where thesupporting substrate was formed. The weakening facilitated a separationof the individual supporting substrates.

The probe fits into the receptacle and is positioned correctly withrespect to the alignment marks 138, 140. The only job for the alignmentmarks 138, 140 is to ensure that the contact pads of the probe be inposition with the subsequently fitted contacting socket of the measuringhead. The other issues of alignment, i.e. minimum tilt and minimumrotation, are taken care of due to the self-alignment. The probe 122front surface is plane parallel with the substrate 114 surface, and theprobe length axis is parallel with the substrate symmetry axis.

The region 119 is the bottom of the probe receptacle. The two holes oretch pits 138, 140 serve as positional alignment marks. The contact padsmust be positioned with a certain care relatively to the receptacle. Forthis purpose, the probe 122 also contains one or two pairs of horizontalline segments 134 and 136. In FIG. 9, these pairs of line segments 134,136 have been used to align the probe in the vertical direction. Thepositional uncertainty with this technique may by as much as 20 μmwithout affecting the subsequent contacting of the probe 122 to themeasuring head.

This active positional alignment is not a required issue but an option.Since the distance from the positional alignment marks is defined fromthe layout of both the probe and the substrate it is possible to shortenthe length of the receptacle (decrease the black area in FIGS. 6 and 9),so that the back end 126 of the probe 122 will be pushed along the probelength axis. In this way the probe 122 will be pushed into alignment ina passive manner in both planar directions when pushed down into thereceptacle. This passive alignment along the length axis is contemplatedto be a bit more uncertain than the active alignment since the sidewallof the probe back end does not define a 35.2° angle with vertical butrather an angle close to 0° to within a few degrees. Thus, the passivealignment along the length axis might require a change in the layout ofthe probe contact pads.

Now, the probe 122 is fit into the receptacle. The width of thereceptacle is sufficiently narrow so that the probe will not be infacial contact with the bottom. In this way, the probe 122 is held inplace entirely because of the contact between the probe sidewalls 124,128 and the receptacle sidewalls 118, 120. The sidewalls are notperfectly plane but may have a surface roughness somewhat around 1 μm orbelow. This has no significance once the probe is fit, but it may implya relatively low limit to the allowable tilt of the probe 122 during theprobe mounting procedure.

No matter how small the surface roughness of the {111}-planes that makeout the sidewalls of the probe 122 and the receptacle, the fitted probe122 will be easily fixed using a slight pressure on the front side ofthe probe 122 body. The mass of the probe 122 is, in a presentlypreferred embodiment of the invention, approximately 4 mg giving agravitational pull in the probe of around 40 μN. In a measuringsituation, the cantilevers of the probe are forced into contact with thesample to be measured with a force summing up to within the range of4-40 μN.

By pressing very modestly on the front surface of the probe 122 with amacroscopic tool, a force of the order of magnitude of 1 N ensures thatthe probe 122 be held in place due to the resulting frictional forcebetween the probe sidewalls and the receptacle sidewall. Thus, the probe122 will not need to be glued in any sense. On the other hand, frontsurface pressure must not be too high as to fix the probe 122irreversibly into the receptacle. Presently, the allowable limits ofthis fixation pressure have not been established, but the idea andproblem regarding the fixation pressure is similar to the craft ofcorrectly fitting a revolving live center into the tailstock of amachine tool.

Sufficient fixation of the probe in accordance with the above-mentionedconsiderations is illustrated in FIG. 10. Here, the probe is illustratedfrom the front side wall—confer FIG. 8. The aligning substrate ismounted into the relevant part of the measuring head, where its twoparallel side edges fit exactly into the measuring heads frame so thatrotation of the substrate is impossible. In a true measuring situation,the measuring head with substrate and probe will be turned upside downso that the probe could fall out. This is, however, not an issue due tothe flex print necessary for contacting. To ensure proper, electricalconnection between the flex print contact pads and the respective probecontact pads, a minimum amount of mechanical force must be exerted bymeans of the locking guide of the flex print.

The locking mechanism for the locking guide can be obtained by anycommercially available method that fulfils the requirements to the forceexerted on the front side of the probe and at the same time allowspositioning of the flex print contact pads within 20 μm. The lockingmechanism must not contain magnetic parts.

In FIG. 10, detail of the probe 122 mounted in a measuring head isviewed towards the front side of the probe 122. The probe 122 itself hasfour cantilevers 162, 164, 166 and 167 pointing directly towards theobserver. The probe 122 fits in the receptacle of the aligning substrate170. The probe 122 is too wide to be able to be in facial contact withthe bottom 172 of the receptacle. Thereby a gap is defined in betweenthe probe and the bottom 172. The bottom 172 may be visible through 119of FIGS. 8 and 9. The substrate 170 fits exactly between the parallelframe jaws 173 a and 173 b of the relevant part of the measuring head.The final fixation of the probe 122 is activated by a contacting flexprint 174 being attached, pressing gently on top of the probe 122.

So far, it has been assumed that the substrate 170 itself is fixed in ameasuring head. However, the substrate 170 is still a necessary part ofthe entire alignment issue. By inspection of FIG. 6 and FIG. 10 itappears, that the width of the substrate is defined by the originalCAD-layout of the photolithographic mask for substrate manufacture.

In practice, there is a certain uncertainty on the width of the finalsubstrate as well as on the width of the receptacle and on the probewidth. This is because the KOH-etch rate in the <111>-directions is notexactly zero, and because of the small uncertainties in the alignment tothe silicon crystal axes. Consequently, the substrate frame in themeasuring head should have a flexible width.

The simplest, and best, way to handle this in practice is to fix one ofthe frame jaws, say the right one 173 b. Then, the left jaws 173 a canbe displaced to the left and to the right relative to the direction inFIG. 10. Near the two ends of the left frame jaw 173 a it is attached tothe main part of the measuring head by two guided springs.

Mounting of a substrate is done by turning the measuring head upsidedown (as in FIG. 10), and pulling the left jaw 173 a to the left. Thesubstrate 170 is laid gently on the flat plane of the measuring head.The left jaw 173 a is slowly released, whereby the substrate will befixated. The opposite side of the substrate, i.e. the region of thesubstrate opposite to the receptacle, is large enough to allow a similarfixation normal to the substrate surface.

As mentioned above, during a measurement the probe in the substrate willturn upside down with respect to the orientation in FIG. 10. Themeasuring situation is sketched in FIG. 11.

FIG. 11 is a schematic side view of the measuring situation. The probe122 turns upside down with respect to FIG. 10. The probe 122 defines anangle with the surface of a test sample of typically 30°. The measuringangle provides space for the flex print 174 and its locking guide 176.The entire measuring head with mounted probe 122 is designed to allow aview of the probe cantilevers both perpendicularly and from a verticaldirection.

The design of the measuring head must anyway leave space for thefixation mechanisms, contacting mechanisms and any optical recognitionsystems. The probe is typically approached to a sample surface with anangle of 30° but smaller angles might be needed in certain applications;in the latter case, the design of probe as well as substrate may simplybe elongated to allow for smaller approach angles. The front end of themeasuring head has a “sharpened” shape in order for the probe to bevisible for the various possible optical detection systems.

As mentioned previously, the gravitational force trying to pull out theprobe in FIG. 11 is a few μN, and, when approaching the probe to thesample, the slight bending of the cantilevers sums to a similar amount.The torque resulting front the cantilever bending force should beincluded since this force attacks at a distance of about 1.5 mm from theprobe body center. However, the rear most set of flex print contact padsare displaced approximately 0.5 mm in the opposite direction, so it iscontemplated that the torque resulting from the contact pad force on theprobe body relates to the cantilever bending torque more or less likethe contact pad force relates to the cantilever bending force.

Thus, once the probe is mounted, the measuring may be performed with theangular alignment of the probe in a contemplated improved manner.

Any kind of SPM-probe will wear and eventually stop functioning. At thisstage, the probe is typically intact from a mechanical point of view.Consequently, there should normally be no need for changing thesubstrate when changing the probe. To remove the probe, one will releasethe measuring head and turn it with the probe facing upwards and releasethe guided flex print. Now, the probe will typically fall out if themeasuring head is turned upside down, due to gravity. This is true ifthe force exerted by the flex print has not been too high. If however,the probe does not fall out by itself, place the measuring head with theprobe turning upwards and then push it gently with set of tweezers or asimilar tool.

The positional alignment marks on the probe and on the self-alignmentsubstrate further allows the probe to be positioned in the receptacle inexactly the same way; it would be handled in a commercial bonding tool.

FIG. 12 is a schematic illustration of an alternative embodiment of arecess 148 formed in a substrate 150. The recess 148 is adapted forreceiving a probe, as described in connection the FIGS. 6-11 . Therecess 148 includes four electrically conductive paths, all designatedby the reference numeral 152, for establishing electrical connectionsbetween the probe and a measuring apparatus. The electrically conductivepaths 152 may be established on the substrate 150 after the formation ofthe recess 148, e.g. by depositing electrically conductive material ontothe surface and the side walls constituting the recess 148.

FIG. 13 is a schematic illustration of a further alternative embodimentof a recess 154 formed in a substrate 156. The recess 154 includes aprotruding part 158 formed on or in the bottom 160 of the recess 154.The protruding part 158 is here illustrated having a truncatedtriangular cross-section, but may, in further alternative embodiments,define a rounded cross-section, a square cross-section, a rectangularcross-section, a triangular cross-section, any polygonal cross-sectionor any combination thereof.

The protruding part 158 may be formed in the bottom wall 160 by applyinga mask after forming a part of the recess 154. The mask may then definean area where the bottom 160 is exposed. This exposed area of the bottom160 is then exposed to an etch reagent, etching away material of thesubstrate, thus leaving material constituting the protruding area 158.

A co-operating recess may be formed in the probe to be received withinthe recess 154. These recesses are contemplated to increase thealignment and mechanical stability of the probe and substrate assembly.

The protruding area 158 is illustrated as being linear, i.e. extendsubstantially perpendicular to the side walls of the recess 154.However, the protruding part may define any geometry, i.e. include turnsor define a non-linear geometry, such as curved, circular,semi-circular, polygonal or any combinations thereof.

Further alternatively, protruding parts may be formed in one or more ofthe side walls of a recess.

Even further alternatively, the above description may be negated, i.e.the protruding parts may be recesses and the recesses may be protrudingparts, viz. a protruding part may be formed on the probe while acorresponding recess may be formed in the recess receiving the probe.

FIGS. 14 a to 14 b schematically illustrate a system comprising twomulti-point probes 160 and 170. Each of the probes 160 and 170 comprisesfour probe arms, designated 162, 164, 166, 168, 172, 174, 176 and 178,respectively.

A test sample is provided and one or more of the probe arms are broughtcontact with the test sample. The test sample is not illustrated inFIGS. 14 a to 14 d. The test sample is in FIGS. 14 a to 14 d consideredas being placed in the plane of the paper. An x-y co-ordinate system isdefined relative to the test sample, and/or the paper. In FIGS. 14 a to14 d only motions in the x-y plane is illustrated, however, movement inall directions or dimensions, i.e. x and/or y and/or z, is possible.

The probes 160 and 170 are cantilever type probes, but other types ofprobes may be used. The cantilever type probes are preferablymicro-fabricated cantilever electrode arrays made withMicro-Electro-Mechanical-System technology (MEMS).

In the sequence illustrated in FIGS. 14 a to 14 d, the probe 160 ismoved parallel to the probe 170. The illustration indicates a movementin substantially one direction or dimension; however, measurementsequences involving movement in more dimensions or directions may beenvisioned and implemented. The probes may be positioned with sub-micronresolution to parallelogram configurations by using piezo-electricactuation, and other sub-micron movement technology or techniques mayalternatively be used.

In the test machine in FIGS. 14 a to 14 d a signal is applied to oneprobe arm 162 and the probe arm 174 is used to measure the receivedsignal. The signal is contemplated to propagate through the test sample.Also, more than one probe arm on the probe 170 may receive or detect thesignal after propagation through the test sample; further, probe arms onthe probe 160 may be used to detect the test signal.

The propagating test signal is illustrated by the punctuated line 180.The signal propagating in a test sample may propagate via a pathdifferent from a straight line.

The movement enables a characterization of the electrical properties ofan area of the surface of the test sample.

As the probe 160 is moved in a controlled way relative to the probe 170,the variations in the measurements are recorded and analyzed. Theanalysis may be performed by either the test machine or a computingdevice attached to or in connection with the test machine.

The analysis is contemplated to provide information regarding anisotropyand electronic transport properties of the material or device undertest.

The speed at which the probe 160 is moved relative to the probe 170, ispreferably constant, but may be varied during the measurement.Alternatively, a series of measurements may be performed at specificlocations, i.e. measurements are performed while the probe 160 is notmoved relative to the probe 170.

The tests performed on a semiconductor device may be circuit tests,conductivity tests, resistance tests or any other electrical propertiesor characterization tests or combinations and/or variations thereof.Furthermore, a magnetic field may be applied over or to the sample,preferably in a direction substantially perpendicular to the planedefined by the surface of the test sample, with the magnetic fielddirection being either away or towards the surface of the test probe.The application of a magnetic field is contemplated to enablemeasurements or determination of characteristic electrical propertiesusing or utilizing the Hall-effect.

FIG. 15 is a schematic view of a system comprising two multi-pointprobes, 182 and 184. The probes 182 and 184 are movable in threedimensions, as indicated by the two co-ordinate systems.

The probes 182 and 184 are each electrically connected to a respectivemultiplex unit 186 and 188 for allowing electrical connection to one ormore electrodes on one or more probe arms at any given time. Themultiplex units 186 and 188 allow transmission of any type of signals,such as AC, DC or HF signals.

The set-up illustrated in FIG. 15 is used for both resistive andcapacitive measurements. The measurements are performed by applying testsignals, i.e. constituted by AC or DC currents, alternatively by HFsignals. The signal is applied to one, alternatively more, probe arms ofone of the test probes, i.e. probe 184.

The signal measured, recorded, collected or received is then processedto obtain the desired information. In the case where AC or DC signalsare applied, the current and the voltage are measured or determined;hereafter, the resistance and/or capacitance is calculated. The signalis recorded or detected at any of the remaining electrodes of any of theremaining probe arms, dependant on the desired configuration.

The HF signals are processed using signal processing such as FFT orother, preferably digital, signal processing schemes algorithms. Theprocessing is performed in a digital signal processor, or alternativelyin analogue signal processing equipment.

In another embodiment, the test sample includes a multitude of electrodepads, the position of the probes 182 and 184 is adjusted to align withone or more of the electrode pads, and the controlled interrelatedmovement or positioning of the probes is then contemplated to provideinformation regarding the performance of the device under test,preferably being a semiconductor device including circuitry, such as anASIC, FPGA, SOC or other similar device.

Further, multiplexing devices may be employed for the independentcontrol of the electrical connections to each of the electrodes of thetest probes, i.e. in the set-up including a plurality of test probescontrol is obtained over each of the electrodes. This multiplexingdevice is contemplated to enable electrical tests with different spatialelectrode configurations, thereby increasing the accuracy of materialtests. Providing a test sample with known properties, such as a testsample having well-known circuitry electrical pad configurations,enables calibration and alignment of the multi-point probes, preferablybeing two or more.

Current and voltage are monitored as a function of the distance betweenthe two probes when performing measurements calibration.

The probes are brought into contact with the test sample whileelectrical signals are transmitted from one or more of the electrodesand recorded, received or detected via one or more of the remainingelectrodes as a function of the interrelated position of the probes. Thecontrolled interrelated movement of the test probes then providesinformation about the alignment of the electrodes, automated calibrationand alignment of the probes may then be performed.

FIG. 16 is a schematic view of an alternative test set-up where theprobes 182′ and 184′ are electrically connected via multiplex units 186′and 188′. The alternative set-up illustrates the possibility to apply atest signal to one or more electrodes of either one or more of the testprobes electrodes. It is then possible to apply a test signal to e.g.two of the probe arms, one on each of the test probes.

Further, it is possible to conduct several, two or more, measurements atthe same time using different or same probe arms by using multiple orseveral signals each being substantially limited to its own frequencyband.

FIG. 17 is a schematic view of an alternative embodiment of a probe 200.The probe comprises a base part 202 and a cantilever 204 extending fromthe base 202. The cantilever 204 is rectangular and has substantiallythe same thickness across the entire cantilever 204.

The probes illustrated in the FIGS. 17-25 comprise a supporting basepart and a single substrate forming the cantilever part and a partconnected to the base part. The supporting base and the substrate may beformed from identical materials or different materials.

FIG. 18 is a schematic illustration of a probe 210 comprising a basepart 212 and a cantilever part 214. The cantilever part extends from thebody 212 and includes areas 216, 218 and 220. The width of the area 218is smaller than the width of the area 216 and 220, respectively. Thedecreased width of the area 218 compared to the areas 216 and 220 iscontemplated to give the cantilever part 214 greater flexibility. Thewidth of the areas 216 and 220 is illustrated as being substantiallyequal.

Comparing the flexibility of the probe 200 illustrated in FIG. 17 andprovided the overall length of the cantilever parts 204 and 214,respectively, are substantially equal, the probe 210 provides greaterflexibility as indicated in table 1.

Table 1 shows the degree of movement along a longitudinal center axis ofthe cantilever parts of the probes as illustrated in the FIGS. 17-25when a force of 5 or 10 micro Newton, respectively, is applied to one ofthe corners of the distal end of the cantilever parts of the testprobes.

Table 2 shows the spring constants of the probes illustrated in theFIGS. 17-25.

TABLE 2 Probename Spring constant/(N/m) Probe200 0.81 Probe210 0.50Probe222 0.40 Probe234 0.22 Probe252 0.17 Probe264 0.33 Probe280 0.28Probe290 0.06

TABLE 1 UpperZ/μm LowerZ/μm Angle/degree Force/μN Probe200 54.58 53.631.360902694 5 Probe200 48.44 46.71 2.478815092 10 Probe210 51.31 49.921.991429077 5 Probe210 42.40 39.75 3.798622703 10 Probe222 47.72 45.972.507490091 5 Probe222 36.03 32.78 4.660405799 10 Probe234 40.21 37.613.726848698 5 Probe234 27.43 23.25 5.998312245 10 Probe252 34.79 31.474.761011744 5 Probe252 22.42 17.56 6.978577604 10 Probe264 47.43 45.362.966380202 5 Probe264 35.65 32.00 5.235498446 10 Probe280 45.21 42.883.339366856 5 Probe280 32.62 28.59 5.782320515 10 Probe290 19.55 −6.7119.14690626 5 Probe290 7.03 −21.09 20.55674872 10

FIG. 19 is a schematic illustration of a probe 222 having a base part224 and a cantilever part 226. The cantilever part 226 comprises threesections or areas 228, 230 and 232. Comparing the probe 222 to the probe210 illustrated in FIG. 18, the area 230 is shorter and narrower thanthe area 218 while the area 232 is larger, i.e. longer and wider thanthe area 220. As seen from table 1, the probe 222 provides a greaterflexibility than the probe 210.

FIG. 20 is a schematic illustration of a probe 234 comprising asupporting body 236 and a cantilever part 238. The cantilever partcomprises three areas or sections 240, 242 and 244. The middle section242 comprises three apertures or openings 246, 248 and 250. The openings246, 248, 250 are illustrated as rectangular openings extending alongthe cantilever 230. The openings 246, 248 and 250 may extend through thesection 242 or may in the alternative extend partly through the section242, thereby being constituted by roofs or trenches.

The section 242 is further illustrated as having a smaller thicknesscompares to the areas 240 and 244. Additionally, the areas 240 and 244comprise angle sides 254, 256, 258, 260. The angle sides arecontemplated to reduce the weight of the cantilever as well as provideimproved flexibility of the cantilever 238.

In the present Figs., the middle sections as illustrated may beperceived as separate parts, however in the presently preferredembodiment the entire cantilever is constructed from a single unitarypiece of material. The bars and apertures are preferably formed byetching the middle section of the cantilever parts.

FIG. 21 is a schematic illustration of a probe 252 having a constructionsimilar to that of the probe 234 shown in FIG. 20. However, the section254 comprises larger apertures or narrower bars compared to the section242 of FIG. 20. As seen in table 1, the probe 252 provides a greaterdegree of angular movement than the probe 234.

The probe 264 illustrated in FIG. 22 has a middle section 266 comprisingtwo wide bars 270 and 274 and two smaller bars 268 and 272 along withtwo side bars 276 and 278.

In the sides of the middle section 266 of the probe 264 the bars 276 and278 form an L-shaped structure with the two smaller bars 268 and 272.The L-shaped structure has been shown to cause the probe to flex in adifferent point compared to the probes not having such as structure inthe cantilever part. The edge or side of the middle section can be saidto have an L-shaped cross-section or

FIG. 23 schematically illustrates a probe 280 with a middle section 282having three equally wide apertures 284, 286 and 288. The overallstructure of the cantilever part is similar to that of the probe 264 ofFIG. 22. The probe 280 has an L-shaped structure like that shown in theprobe of FIG. 22.

FIG. 24 is a schematic illustration of a probe 290 having a longcantilever part 292 extending from a supporting body 294. The cantilever292 includes a head part 296 being wider than the cantilever partconnecting the cantilever to the supporting body 294. On the edge 298 ofthe head 296 remote from the body 294 a pultruding part is formed. Thepart of the edge 298 provides additional weight to the cantilever headand, as is seen in table 1, the structure provides a large degree ofmovement compared to the other probes.

FIG. 25 is a zoomed view of a part of the probe 292 of FIG. 24.

It is to be understood, that the probe head or distal part of thecantilever of the probe illustrated in the FIGS. 24 and 25 may becombined with any of the other probe configurations illustrated anddescribed in the present specification.

Table 1 includes simulation data from the probes as described in theFIGS. 17-24 and described above. The table includes results of applyinga force of 5 or 10 micro Newton one side of the cantilever part of theprobe. The results show the angular movement of the probes along withthe movement in said direction.

The probes illustrated in the FIGS. 17-24 have been mentioned as havingapertures, however, in further alternative embodiments the probes mayhave only partially etched areas so that the middle areas or sectionsdefine multiple areas with different thicknesses. These areas withdifferent thicknesses are contemplated to give the probes, or at leastthe cantilever part of the probes, an improved flexibility.

In a test machine for testing electrical properties of test samples atraditional method for determining if the test probe has had sufficientelectrical and mechanical contact with the test sample is to examinemarks and tracks made in the test sample after pushing the test probeinto or onto the test sample. Traditionally, the method involves movingthe test probe into contact with the test sample and after the testprobe has made contact with the test sample, the test probe is moved orpressed even further into the test sample thereby creating marks ortracks in the contact area of the test sample. A term sometimes used forthis process is overdrive.

The marks and/or tracks are then inspected to evaluate the quality ofthe electrical contact between the test probe and the test sample. Theevaluation is then only done after the test has been performed and thetest probe has been moved away from the test sample, also, theevaluation is only done indirectly.

The probes and test machine described herein may be used for analternative method of verifying, the electrical contact between the testprobe and the test sample. The alternative method involved having twoprobe heads in contact with the test area, or each of the test areas, ofthe test sample thereby enabling a two-point measurement where theelectrical resistance between the two test probe heads is a directmeasurement of the electrical contact between the test probe and thetest sample.

The determination of the resistance may include sending or transmittingan electrical signal trough one of the test probe heads in contact withthe test area and sampling or measuring the resultant signal on theother test probe head. In alternative embodiments, more than two testprobe heads may be in contact with the test area.

The electrical signal may be a DC signal or an AC signal and may be highor low frequency, such as HF or RF.

The present invention may incorporate any of the features of thefollowing points characterizing the invention:

-   1. A probe for testing electric properties on a specific location of    a test sample, comprising:    -   a supporting body defining opposite first and second parts        constituting a flexible cantilever part being flexible in one        direction and a base part respectively, the cantilever part        defining an outer planar surface substantially perpendicular to        the one direction, the base part being adapted for being fixated        in a co-operating testing machine,    -   at least one conductive probe arm in the cantilever part, each        of the at least one conductive probe arm being positioned        opposite the base part,    -   the cantilever part defining opposite first and second regions,        the second region being in contact with the base part, the first        region defining first and second side surfaces, each of the        first and second side surfaces defining a first angle with the        outer planar surface, a first width defined between the first        and the second side surfaces, the second region defining third        and fourth side surfaces, each of the third and fourth side        surfaces defining a second angle with the outer planar surface,        a second width defined between the third and the fourth side        surfaces, and    -   the second width being equal to or smaller that the first width.-   2. The probe according to point 1 wherein the first and second side    surfaces being substantially parallel the third and fourth side    surfaces being substantially parallel.-   3A. The probe according to point 1 or 2, wherein the first angle is    between 60 to 90 degrees the second angle is approximately 60 to 90    degrees and the first angle being identical to or different from the    second angle.-   3B. The probe according to point 1 or 2, wherein the first angle is    between 60 to 90 degrees, preferably less than 90 degrees the second    angle is approximately 60 to 90 degrees preferably less than 90    degrees, and the first angle being identical to or different from    the second angle.-   4. The probe according to any of the points 1-3A or 1-3B, wherein    the first region further defines a first top surface and an    opposite, parallel first bottom surface, and the second region    further defines a second top surface and an opposite, parallel    second bottom surface, the base part defining a third top surface,    the first, the second and the third top surface being substantially    parallel,    -   the outer planar surface being constituted by the first top        surface and/or the second top surface,    -   a first thickness defined between the first top surface and the        first bottom surface,    -   a second thickness defined between the second top surface and        the second bottom surface,    -   the second thickness being smaller than or equal to the first        thickness.-   5. The probe according to point 4, wherein the second thickness is    defined across all of the second regions area a specific part of the    second region.-   6. The probe according to point 4 or 5, wherein the first top    surface and the second top surface being in substantially coplanar    the first top surface and the third top surface being substantially    coplanar, the second top surface and the third top surface being    substantially coplanar, none of the first, second or third top    surfaces being coplanar.-   7. The probe according to point 4 or 5, wherein the first and the    second bottom surfaces are substantially coplanar.-   8. The probe according to any of the preceding points, wherein    -   the second region includes at least one aperture extending from        the second top surface to the second bottom surface.-   9. The probe according to any of the preceding points, wherein    -   the second region includes at least one indentation extending        less than the second thickness.-   10. The probe according to any of the points 8 or 9, wherein at    least one of the apertures or the indentations define an opening    having a substantially circular geometry, a substantially oval    geometry, a substantially square geometry, a substantially oblong    geometry, a substantially triangular geometry, a truncated    triangular geometry, any polygonal geometry or any combinations    thereof.-   11. The probe according to any of the preceding points, wherein    -   the second region includes at least one groove in the second top        surface in the second bottom surface.-   12. The probe according to point 11, wherein at least one of the at    least one groove extends from the third side to the fourth side.-   13. The probe according to point 11, wherein the at least one groove    extends less that the second width.-   14. The probe according to any of the points 11-13 wherein at least    one of the grooves defines a rounded cross-section, a square    cross-section, a rectangular cross-section, a triangular    cross-section, a truncated triangular cross-section, any polygonal    cross-section or any combination thereof.-   15. The probe according to any of the preceding points, wherein    -   the third the fourth side include a trench extending at least        partly from the second top surface to the second bottom surface        or from the second bottom surface to the second top surface.-   16. The probe according to point 15, wherein    -   the trench defines a rounded cross-section, a square        cross-section, a rectangular cross-section, a triangular        cross-section, a truncated triangular cross-section or any        combination thereof.-   17. The probe according to any of the preceding points, wherein the    probe is substantially made from a metallic material, an alloying, a    semiconductor material, a crystalline or an amorphous material, or    any combination thereof; preferably the probe is made from SiO₂,    Si₃N₄, or Si, or is a SOI device or alternatively a layered    structure comprising any of the mentioned materials.-   18. The probe according to any of the preceding points, wherein the    probe further includes conductive paths for establishing electrical    connections to each of the plurality of conductive probe arms.-   19. The probe according to point 17, wherein the conductive paths    extend from the base part to the cantilever part.-   20. The probe according to any of the preceding points, wherein the    plurality of conductive probe arms are positioned at the outer    planar surface.-   21. The probe according to any of the preceding points, wherein    -   the first width being 50 to 800 micron, such as 75 to 750        micron, such as 75 to 500 micron, such as 80 to 350 micron, such        as 85 to 250 micron, such as 90 to 150 micron, such as 60 to 90        micron, such as 90 to 110 micron, such as 110 to 190 micron,        such as 190 to 240 micron, such as 240 to 290 micron, such as        290 to 340 micron, such as 340 to 440 micron, such as 440 to 550        micron, such as 550 to 650 micron, such as 650 to 800 micron,        preferably 100 micron, and/or    -   the second width being 40 to 300 micron, such as 50 to 250, such        as 75 to 200 micron, such as 100 to 175 micron, such as 120 to        150, such as 40 to 80 micron, such as 80 to 120 micron, such as        120 to 160 micron, such as 160 to 200 micron, such as 200 to 230        micron, such as 230 to 280 micron, such as 280 to 300 micron.-   22. The probe according to any of the points 1-20, wherein:    -   the first width being 0.1 cm to 6 cm, such as 1 cm to 5.5 cm,        such as 1.5 cm to 5 cm, such as 2 cm to 4.5 cm, such as 2.5 cm        to 4 cm, such as 3 cm to 3.5 cm, such as 0.1 cm to 0.5 cm, such        as 0.5 cm to 1 cm, such as 1 cm to 1.5 cm, such as 1.5 to 2 cm,        such as 2 cm to 2.5 cm, such as 2.5 cm to 3 cm, such as 3 cm to        3.5 cm, such as 3.5 cm to 4 cm, such as 4 cm to 4.5 cm, such as        4.5 to 5 cm, such as 5 cm to 5.5 cm, such as 5.5 cm to 6 cm, and    -   the second width being 0.1 cm to 6 cm, such as 1 cm to 5.5 cm,        such as 1.5 cm to 5 cm, such as 2 cm to 4.5 cm, such as 2.5 cm        to 4 cm, such as 3 cm to 3.5 cm, such as 0.1 cm to 0.5 cm, such        as 0.5 cm to 1 cm, such as 1 cm to 1.5 cm, such as 1.5 to 2 cm,        such as 2 cm to 2.5 cm, such as 2.5 cm to 3 cm, such as 3 cm to        3.5 cm, such as 3.5 cm to 4 cm, such as 4 cm to 4.5 cm, such as        4.5 to 5 cm, such as 5 cm to 5.5 cm, such 5.5 cm to 6 cm.-   23. The probe according to any of the preceding points, wherein the    cantilever part have rounded edges at the distal end.-   24. A testing apparatus for testing electric properties on a    specific location of a test sample, comprising:    -   (a) means for receiving and supporting the test sample;    -   (b) electric properties testing means including electric        generator means for generating a test signal and electric        measuring means for detecting a measuring signal;    -   (c) a probe for testing electric properties on a specific        location of a test sample, comprising:        -   1. a supporting body defining opposite first and second            parts constituting a flexible cantilever part being flexible            in one direction and a base part respectively, the            cantilever part defining an outer planar surface            substantially perpendicular to the one direction, the base            part being adapted for being fixated in a co-operating            testing machine,        -   2. a plurality of conductive probe arms in the cantilever            part each of the conductive probe arms freely extending from            the cantilever part opposite the base part giving each of            the conductive probe arms flexible motion,        -   3. the cantilever part defining opposite first and second            regions, the second region being in contact with the base            part, the first region defining first and second side            surfaces, each of the first and second side surfaces            defining a first angle with the outer planar surface, a            first width defined between the first and the second side            surfaces, the second region defining third and fourth side            surfaces, each of the third and fourth side surfaces            defining a second angle with the outer planar surface, a            second width defined between the third and the fourth side            surfaces,        -   4. the second width being equal to smaller than the first            width,    -   (d) reciprocating means for moving the probe relative the test        sample so as to cause the conductive probe arms to be contacted        with the specific location of the test sample for performing the        testing of electric properties thereof.-   25. The testing apparatus according to point 24, wherein the    electric properties testing means further comprises means for    electric properties probing of the test sample.-   26. The testing apparatus according to point 24-25, wherein the    reciprocating means further comprises holding means adapted for    co-operatively receiving the base part of the probe.-   27. The testing apparatus according to point 24-26, further    comprising means for positioning the holding means across the test    sample and recording of a location of the holding means relative to    the test sample.-   28. The testing apparatus according to point 24-27, wherein the    means for positioning comprises maneuverability in all spatial    directions, being directions coplanar to the test sample and    directions perpendicular to the test sample.-   29. The testing apparatus according to point 24-28, wherein the    means for positioning further comprises means for angular movement    of the holding means, such as to provide angular positions for the    means for the probe.-   30. The testing apparatus according to point 24-29, wherein the    means for positioning further comprises means for angular movement    of the holding means along an axis parallel to surface of the test    sample, such as to provide angular positions for the means for the    probe.-   31. The testing apparatus according to point 24-30, wherein the    means for positioning further comprises means for angular movement    of the holding means along an axis perpendicular to surface of the    test sample, such as to provide angular positions for the means for    the probe.-   32. The testing apparatus according to point 24-31, wherein the    means for positioning further comprises means for sensing contact    between the test sample and the means for the probe.-   33. The testing apparatus according to point 24-32, wherein the    probe further includes any of the features of any of the points    2-23.-   34. A method for providing alignment of a probe relative to a    supporting substrate, comprising the steps of:    -   providing the supporting substrate defining a planar surface and        an edge, the substrate further defining a first crystal plane,    -   providing a first mask at the surface of the supporting        substrate, the first mask defining a first exposed area on the        surface at the edge,    -   providing a specific etch reagent, a recess formed by the etch        reagent etching the first exposed area, the recess defining a        first sidewall an opposing second sidewall, an end wall remote        from the edge, and a bottom wall,    -   providing a probe substrate defining a planar surface and a        second crystal plane identical to the first crystal plane,    -   positioning the probe substrate so that the first and the second        crystal planes are positioned identically when forming the probe        from the probe substrate using the specific etch reagent, the        probe defines congruent surfaces to the first sidewall and the        second sidewall.-   35. The method according to point 34, wherein the specific etch    reagent is provided at a specific concentration.-   36. The method according to any of the points 34 or 35, further    comprising providing a specific temperature at which the etching is    performed.-   37. The method according to any of the points 34-36, further    comprising providing a specific pressure at which the etching is    performed.-   38. The method according to any of the points 34-37, where the    specific etch reagent the temperature the specific pressure is    applied for a specific period of time.-   39. The method according to any of the points 34-38, wherein the    supporting substrate the probe substrate is Si, GaAs, or any other    semiconductor material.-   40. The method according to any of the points 34-39, further    comprising:    -   providing a second mask at the bottom wall, the second mask        defining a second exposed area, a protruding area formed in the        bottom surface by etching the second exposed area using the        specific etch reagent.-   41. The method according to point 40, wherein the protruding area    defines a cross-section having a substantially square, rectangular,    triangular, truncated pyramid, polygonal, semi-circular, partly    circular, semi-elliptical, partly elliptical geometry or any    combinations thereof.-   42. The method according to any of the points 34-41, further    comprising providing at least one conducting area in the first    sidewall the second sidewall the end wall.-   43. The method according to point 42, further comprising extending    the at least one conducting area onto the planar surface.-   44. The method according to any of the points 34-43, further    comprising positioning the probe in alignment with the recess.-   45. An apparatus for providing alignment of a probe relative to a    supporting substrate, comprising:    -   the supporting substrate defining a surface and an edge, the        supporting substrate defining a first crystal plane,    -   a recess formed by a specific etch reagent in the surface at the        edge in the supporting substrate, the recess defining a first        sidewall an opposing second sidewall, an end wall remote from        the edge, and a bottom wall,    -   a probe formed from a probe substrate defining a surface and a        second crystal plane identical to the first crystal plane using        the specific etch reagent so that the probe defines congruent        surfaces to the first sidewall and the second sidewall, the        probe received in the recess.-   46. The apparatus according to point 45, wherein the probe    comprises:    -   a supporting body defining opposite first and second parts        constituting a flexible cantilever part being flexible in one        direction and a base part respectively, the cantilever part        defining an outer planar surface substantially perpendicular to        the one direction, the base part being adapted for being        received in the recess,    -   at least one conductive probe arm in the cantilever part, each        of the at least one conductive probe arm being positioned        opposite the base part,    -   the cantilever part defining opposite first and second regions,        the second region being in contact with the base part, the first        region defining first and second side surfaces, each of the        first and second side surfaces defining a first angle with the        outer planar surface, a first width defined between the first        and the second side surfaces, the second region defining third        and fourth side surfaces, each of the third and fourth side        surfaces defining a second angle with the outer planar surface,        a second width defined between the third and the fourth side        surfaces, and    -   the second width being equal to smaller than the first width.-   47. The apparatus according to any of the points 45 or 46, wherein    the bottom wall includes a protruding part and the probe includes a    co-operating groove.-   48. The apparatus according to point 47, wherein the protruding part    defines a substantially square, rectangular, triangular, truncated    pyramid, polygonal, semi-circular, partly circular, semi-elliptical,    partly elliptical cross-section or any combinations thereof.-   49. The apparatus according to any of the points 47 or 48, wherein    the protruding part extends from the first side wall to the second    side wall.-   50. The apparatus according to any of the points 47 or 48, wherein    the protruding part extends from the first side wall to the end    wall, the protruding part extends from the second side wall to the    end wall.-   51. The apparatus according to any of the points 45-50, wherein the    supporting substrate further includes at least one substrate    alignment mark and the probe includes at least one corresponding    probe alignment mark.-   52. The apparatus according to point 51, wherein the substrate    alignment mark the probe alignment mark is formed as an etched    alignment recess and/or alignment protruding part.-   53. The apparatus according to any of the points 45-52, wherein the    supporting substrate comprises at least two recesses at least two    probes.-   54. A testing apparatus for testing electric properties on a    specific location of a test sample, comprising:-   (b) means for receiving and supporting the test sample;-   (c) electric properties testing means including electric generator    means for generating a test signal and electric measuring means for    detecting a measuring signal;    -   a probe for testing electric properties on a specific location        of a test sample, the probe received in an apparatus for        providing alignment of the probe relative to a supporting        substrate, the apparatus comprising:        -   the supporting substrate defining a surface and an edge, the            substrate defining a first crystal plane,        -   a recess formed by a specific etch reagent in the surface at            the edge of the supporting substrate, the recess defining a            first sidewall an opposing second sidewall, an end wall            remote from the edge, and a bottom wall defining a minimum            height from the surface,    -   the probe formed from a probe substrate defining a surface and a        second crystal plane identical to the first crystal plane using        the specific etch reagent so that the probe defines congruent        surfaces to the first sidewall and the second sidewall, the        probe received in the recess,-   (d) reciprocating means for moving the probe relative the test    sample so as to cause one or more conductive probe arms positioned    on the probe to be contacted with the specific location of the test    sample for performing the testing of electric properties thereof.-   55. The testing apparatus according to point 54, wherein the    electric properties testing means further comprises means for    electric properties probing of the test sample.-   56. The testing apparatus according to point 54 or 55, further    comprising means for positioning the holding means across the test    sample and recording of a location of the holding means relative to    the test sample.-   57. The testing apparatus according to any of the points 54-56,    wherein the means for positioning comprises maneuverability in all    spatial directions, being directions coplanar to the test sample and    directions perpendicular to the test sample, and/or means for    angular movement of the holding means, such as to provide angular    positions for the means for the probe.-   58. The testing apparatus according to any of the points 54-57,    wherein the means for positioning further comprises means for    angular movement of the holding means along an axis parallel to    surface of the test sample, such as to provide angular positions for    the means for the probe.-   59. The testing apparatus according to any of the points 54-58,    wherein the means for positioning further comprises means for    angular movement of the holding means along an axis perpendicular to    surface of the test sample, such as to provide angular positions for    the means for the probe.-   60. The testing apparatus according to any of the points 54-59,    wherein the means for positioning further comprises means for    sensing contact between the test sample and the means for the probe.-   61. The testing apparatus according to any of the points 54-60,    wherein the probe further includes any of the features of any of the    points 35-53.-   62. A method for testing electrical properties comprising:    -   i) providing a test sample defining a first surface, an area        defined on the first surface,    -   ii) providing a first test probe comprising:        -   a first plurality of probe arms each including at least one            electrode for contacting a respective location on the test            sample,    -   iii) providing a second test probe comprising:        -   at least one probe arm including at least one electrode for            contacting a location on the test sample,    -   iv) providing a test apparatus including a first and a second        holder for receiving the first and the second test probes        respectively, each of the holders comprising positioning devices        for positioning relocating each of the holders in three        dimensions, the test apparatus being electrically connected to        each of the electrodes of the first test probe and to the at        least one electrode of the second test probe, the test apparatus        further comprising a sample holder for receiving and holding the        test sample in a specific orientation relative to the first and        the second test probe,    -   v) positioning the electrodes of the probe arms of the first        test probe in contact with the area,    -   vi) positioning the at least one electrode of the at least one        probe arm of the second test probe in contact with the area at a        location remote from the first test probe,    -   vii) transmitting a test signal from at least one of the        electrodes of the first test probe, or, in the alternative from        the at least one electrode of the second test probe, and    -   viii) detecting the test signal transmission between the first        and the second test probe.-   63. The method according to point 62, the method further comprising    intermediate steps after the step vi):    -   a) providing a magnetic field generator for generating a        magnetic field,    -   b) positioning the magnetic field generator so that the field        lines of the magnetic field defines a specific orientation with        the area of the test sample.-   64. The method according to any of the points 62 or 63, the method    further comprising the steps of:    -   c) relocating or moving the first test probe relative to the        area and/or relocating or moving the second test probe relative        to the area, and    -   d) repeating step vii) the intermediate steps a) b).-   65. A method for testing electrical properties comprising:    -   i) providing a test sample defining a first surface, an area        defined on the first surface,    -   ii) providing a first test probe comprising:        -   a first plurality of probe arms each including at least one            electrode for contacting a respective location on the test            sample,    -   iii) providing a second test probe comprising:        -   at least one probe arm including at least one electrode for            contacting a location on the test sample,    -   iv) providing a test apparatus including a first and a second        holder for receiving the first and the second test probes        respectively, each of the holders comprising positioning devices        for positioning relocating each of the holders in three        dimensions, the test apparatus being electrically connected to        each of the electrodes of the first test probe and to the at        least one electrode of the second test probe, the test apparatus        further comprising a sample holder for receiving and holding the        test sample in a specific orientation relative to the first and        the second test probe,    -   v) positioning the electrodes of the probe arms of the first        test probe in contact with the area,    -   vi) positioning the at least one electrode of the at least one        probe arm of the second test probe in contact with the area at a        location remote from the first test probe,    -   vii) providing a magnetic field generator for generating a        magnetic field,    -   viii) positioning the magnetic field generator so that the field        lines of the magnetic field defines a specific orientation with        the area of the test sample, and    -   ix) detecting electrical signals at the first the second test        probes.-   66. The method according to point 64, the method further comprising    the steps of:    -   a) transmitting a test signal from at least one of the        electrodes of the first test probe, or, in the alternative from        the at least one electrode of the second test probe, and    -   b) detecting the test signal transmission between the first and        the second test probe.-   67. The method according to any of the points 65 or 66, the method    further comprising the steps of:    -   c) relocating or moving the first test probe relative to the        area and/or relocating or moving the second test probe relative        to the area, and    -   d) repeating step ix) the steps a) b).-   68. The method according to any of the points 62-67, wherein the    second test probe comprises a plurality of probe arms each    comprising at least one electrode.-   69. The method according to any of the points 67-68, wherein the    positioning-devices are constituted by piezo-electrical actuators.-   70. The method according to any of the points 62-69, wherein a    multitude of electrode pads are defined on the surface of the test    sample, the method further comprising bringing a first specific    electrode in contact with a second specific electrode pad, bringing    a third specific electrode in contact with a fourth specific    electrode pad,    -   transmitting a test signal from the first or the third specific        electrode, and    -   detecting the test signal transmission between the third or the        first electrode, respectively.-   71. The method according to any of the points 62-70, wherein the    probe arms of the first test probe are substantially parallel and    the at least one probe arm of the second defines a longitudinal    length.-   72. The method according to point 71, further comprising:    -   arranging the first and the second test probes so that the probe        arms of the first test probe are substantially parallel with the        at least one probe arm of the second probe arm.-   73. The method according to point 71, further comprising:    -   arranging the first and the second test probes so that the probe        arms of the first test probe are in an orientation substantially        orthogonal with the at least one probe arm of the second probe        arm.-   74. The method according to any of the points 62-73, further    comprising: providing at least one additional test probe comprising:    -   at least one probe arm including at least one electrode for        contacting a location on the test sample,    -   and    -   providing at least one additional holder in the test apparatus        for receiving and holding the at least one additional test        probe.-   75. The method according to point 74, wherein the at least one probe    arm of the at least one additional test probe define a longitudinal    length, the method further comprising:    -   arranging the first, the second and the at least one additional        test probe in a arrangement where the probe arms of the first        probe defines a first angle with the at least one probe arm of        the second test probe, and the probe arms of the first probe        define a second angle with the one probe arm of the at least one        additional test probe.-   76. An apparatus for testing electrical properties comprising:    -   a housing,    -   a first and a second holder for receiving a first and a second        test probe, respectively, mounted in the housing, each of the        holders comprising positioning devices for positioning        relocating each of the holders in three dimensions,    -   the first test probe comprising:        -   a first plurality of probe arms each including at least one            electrode for contacting a respective location on the test            sample,    -   the second test probe comprising:        -   at least one probe arm including at least one electrode for            contacting a location on the test sample,    -   the test apparatus electrically connected to each of the        electrodes of the first test probe and to the at lease one        electrode of the second test probe, the test apparatus further        comprising a sample holder for receiving and holding a test        sample in a specific orientation relative to the first and the        second test probe, the test sample defining a first surface, an        area defined on the first surface,    -   a signal generator for generating a test signal electrically        connected to a transmitter device for transmitting the test        signal via at least one of the electrodes of the first test        probe in contact with the area, or, in the alternative, via the        at least one electrode of the second test probe in contact with        the area, and    -   a detection device for detecting the test signal transmission        between the first and the second test probe.-   77. The apparatus according to point 76, wherein the    positioning-devices are constituted by piezo-electrical actuators.-   78. The apparatus according to any of the points 76-77, wherein the    probe arms of the first test probe are substantially parallel and    the at least one probe arm of the second defines a longitudinal    length,    -   the first and the second test probes arranged so that the probe        arms of the first test probe are substantially parallel with the        at least one probe arm of the second probe arm, or    -   the first and the second test probes arranged so that the probe        arms of the first test probe are in an orientation substantially        orthogonal with the at least one probe arm of the second probe        arm.-   79. The apparatus according to any of the points 76-78, further    comprising:    -   at least one additional test probe comprising:        -   at least one probe arm including at least one electrode for            contacting a location on the test sample,    -   and    -   at least one additional holder in the housing of the test        apparatus for receiving and holding the at least one additional        test probe.-   80. The apparatus according to point 79, wherein the at least one    probe arm of the at least one additional test probe define a    longitudinal length, the apparatus further comprising:    -   the first, the second and the at least one additional test probe        arranged in a arrangement where the probe arms of the first        probe define a first angle with the at least one probe arm of        the second test probe, and the probe arms of the first probe        define a second angle with the one probe arm of the at least one        additional test probe.

Any of the features mentioned in the points may be combined.

1. An apparatus for providing alignment of a probe relative to asupporting substrate defining a first surface, an edge, and a firstcrystal plane, comprising: a recess formed by an etch reagent in saidsurface at said edge in said supporting substrate, said recess defininga first sidewall, an opposing second sidewall, an end wall remote fromsaid edge, and a bottom wall; and a probe configured to be received insaid recess and formed from a probe substrate defining a second surfaceand a second crystal plane identical to said first crystal plane usingsaid etch reagent so that said probe defines surfaces that are alignedwith said first sidewall and said second sidewall when said probe isreceived in said recess; wherein said supporting substrate includes asubstrate alignment mark and said probe includes a corresponding probealignment mark.
 2. The apparatus according to claim 1, wherein saidprobe comprises: a supporting body defining opposite first and secondparts constituting a flexible cantilever part being flexible in onedirection and a base part respectively, said cantilever part defining anouter planar surface substantially perpendicular to said one direction,said base part being adapted for being received in said recess, aconductive probe arm in said cantilever part, said conductive probe armbeing positioned opposite said base part, said cantilever part definingopposite first and second regions, said second region being in contactwith said base part, said first region defining first and second sidesurfaces, each of said first and second side surfaces defining a firstangle with said outer planar surface, a first width defined between saidfirst and said second side surfaces, said second region defining thirdand fourth side surfaces, each of said third and fourth side surfacesdefining a second angle with said outer planar surface, a second widthdefined between said third and said fourth side surfaces, and saidsecond width being equal to or smaller than said first width.
 3. Theapparatus according to claim 1, wherein said bottom wall includes aprotruding part and said probe includes a co-operating groove.
 4. Theapparatus according to claim 3, wherein said protruding part defines across-section selected from the group consisting of square, rectangular,triangular, truncated pyramid, polygonal, semi-circular, partlycircular, semi-elliptical, partly elliptical cross-section and anycombinations thereof.
 5. The apparatus according to claim 3, whereinsaid protruding part extends from said first side wall to said secondside wall.
 6. The apparatus according to claim 3, wherein saidprotruding part extends from at least one of said first and second sidewalls to said end wall.
 7. The apparatus according to claim 1, whereinsaid supporting substrate alignment mark is formed as an etchedalignment recess on the supporting substrate.
 8. The apparatus accordingto claim 1, wherein said supporting substrate comprises at least tworecesses and at least two probes.
 9. A testing apparatus for testingelectric properties on a specific location of a test sample, comprising:(a) means for receiving and supporting said test sample; (b) electricproperties testing means including electric generator means forgenerating a test signal and electric measuring means for detecting ameasuring signal; (c) a probe configured for testing electric propertieson a location of said test sample, said probe being operable to receivesaid test signal and to return said measuring signal, said probe beingreceived in an apparatus for providing alignment of said probe relativeto a supporting substrate that defines a surface, an edge, and a firstcrystal plane, said apparatus comprising: a recess formed by a etchreagent in said surface at said edge of said supporting substrate, saidrecess defining a first sidewall, an opposing second sidewall, an endwall remote from said edge, and a bottom wall defining a minimum heightfrom said surface, wherein said probe is configured to be received insaid recess and is formed from a probe substrate defining a surface anda second crystal plane identical to said first crystal plane using saidetch reagent so that said probe defines surfaces that are aligned withsaid first sidewall and said second sidewall when said probe is receivedin said recess, and wherein said supporting substrate includes asubstrate alignment mark and said probe includes a corresponding probealignment mark, and (d) reciprocating means for moving said proberelative to said test sample so as to cause one or more conductive probearms positioned on said probe to be contacted with said location of saidtest sample for performing said testing of electric properties thereof.10. The testing apparatus according to claim 9, said electric propertiestesting means further comprising means for electric properties probingof said test sample.
 11. The testing apparatus according to claim 9,wherein said reciprocating means includes holding means configured toreceive the probe, the apparatus further comprising means forpositioning said holding means across said test sample and recording ofa location of said holding means relative to said test sample.
 12. Thetesting apparatus according to claim 11, wherein said means forpositioning is maneuverable in all spatial directions, being directionscoplanar to said test sample and directions perpendicular to said testsample, and includes means for angular movement of said holding means,so as to provide angular positions for said probe.
 13. The testingapparatus according to claim 11, wherein said means for positioningfurther comprises means for angular movement of said holding means alongan axis parallel to surface of said test sample, so as to provideangular positions for said probe.
 14. The testing apparatus according toclaim 11, wherein said means for positioning further comprises means forsensing contact between said test sample and said probe.